There's a lot of differing opinion on how much fluff, background and world building a wargame must do.
Few people are attracted to a game based on mechanics (the how); usually, they are attracted to the game by the background/world/miniatures (what, why). Often we play a game despite the rules - or merely put up with them. So we could argue background/world/aesthetic is more important than mechanics in attracting players.
There is a huge range of personal opinion here: some will prefer "just the rules, ma'am" and no more than a paragraph or two orientating them to the wargame world; others love deep background narrative and lore to drive their games. The most popular wargame (40K) makes it hard to suggest that innovative rule mechanics matter more than shiny toys and cool lore.
Now we've established lore and world building will be very subjective, but are usually very important....
My shower thought I am exploring is: How much worldbuilding is too much?
I am a huge reader; my personal man cave has many thousands of books, and my kids are huge readers too. I often read them "older" books and we like to discuss elements of the text. My kids like Brandon Sanderson, and while I don't enjoy his writing style, I do admire his worldbuilding, which tends to be consistent to its own internal logic and he seems to recognise his own enthusiasm for worldbuilding and make an effort to reign himself in. In contrast to say the magic of Harry Potter (which I'm reading to my 8 year old) which has no logic to it whatsoever.
However, thinking about this question (in context of books) lead to a second question:
Is the worldbuilding for the readers (aka player's) benefit, or the writers benefit (aka game designers)?
World building seems pretty self indulgent. The minute you have your own languages, and whole pages of maps, and your own encyclopedia - that's too far. Maybe when you're a legend like Tolkien who pretty much invented the genre and it's published after he dies due to the demands of fans... then OK.
A lot of time in books, world building is an excuse for a writer to waffle on, to create for his own enjoyment, oblivious to the eye-rolls of his readers.
Can there be too much world building?
I find Star Wars guilty of this. Everything has a name. Everything is explained in detail. Everything has its own Wookiepedia article. The more TV shows and movies they churn out exploring every last detail or every character, the less magic there is, for me anyway. Half the shows premises "What did Obi Wan do between Clone Wars and New Hope" answered questions no one really cared about to ask.
Background and aesthetic (cool lore, cool minis) is supposed to stimulate your wargaming. But can worldbuilding be harmful to creativity and imagination?
Googling around I found this wonderful quote by a sci fi editor:
Every moment of a science fiction story must represent the triumph of writing over worldbuilding.
Worldbuilding is dull. Worldbuilding literalises the urge to invent. Worldbuilding gives an unneccessary permission for acts of writing (indeed, for acts of reading). Worldbuilding numbs the reader’s ability to fulfil their part of the bargain, because it believes that it has to do everything around here if anything is going to get done.
Above all, worldbuilding is not technically neccessary. It is the great clomping foot of nerdism. It is the attempt to exhaustively survey a place that isn’t there. A good writer would never try to do that, even with a place that is there. It isn’t possible, & if it was the results wouldn’t be readable: they would constitute not a book but the biggest library ever built, a hallowed place of dedication & lifelong study. This gives us a clue to the psychological type of the worldbuilder & the worldbuilder’s victim, & makes us very afraid.
When I use the term “worldbuilding fiction” I refer to immersive fiction, in any medium, in which an attempt is made to rationalise the fiction by exhaustive grounding, or by making it “logical in its own terms”, so that it becomes less an act of imagination than the literalisation of one. Representational techniques are used to validate the invention, with the idea of providing a secondary creation for the reader to “inhabit”; but also, in a sense, as an excuse or alibi for the act of making things up, as if to legitimise an otherwise questionable activity. This kind of worldbuilding actually undercuts the best and most exciting aspects of fantastic fiction, subordinating the uncontrolled, the intuitive & the authentically imaginative to the explicable; and replacing psychological, poetic & emotional logic with the rationality of the fake.
~ M. John Harrison
Most wargame fluff is badly written. Usually by enthusiastic amateurs. So yeah, we don't want to give a bad writer "unecessary permission to write." Probably the only wargame-related books I've not minded were by Dan Abnett - which were fun - but only 'decent.' Harsh reality: Most wargaming background lore is just an excuse for an author to subject us to their bad writing.
Too much background removes the players ability to invent. If all 21 space marine legions have their entire history, heraldy and paint schemes - then it may constrain my creativity in making my own custom legion. It undercuts creativity. I enjoy MESBG but (because of the strong lore) I tend to feel compelled to either follow the movies or the official GW schemes - everyone knows what Gandalf and Aragon look like. It's why I'm unenthusiastic about Star Wars minis. Whereas I've never got into the Warmachine, or Confrontation much so my minis tend to be whatever the heck I think looks cool. Way more creative and fun.
Is worldbuilding technically necessary in wargames? To what degree? What is needed?
I'd say that RPGs, specifically, need world-building. In order to roleplay as an elven sorceress in Middleheim is; you need to know about elves, sorceresses and Middlehiem in general in order to properly inhabit your role. Like a method actor, the more you understand your role, the better you can play it. So players books exhaustively explaining every aspect of the RPG "world" seem quite sensible.
But a wargame is not quite the same. You are a commander, a general, a squad leader. You may need to know why you are fighting - although "cost wargs are cool" is all the reason my son needs - and that's fine. You probably need to know what tactics work best - what actions you take (input) will get the best result (output). But how much more do you need?
If the game is about WW2 and the game mechanics accurately represent this genre (this is where mechanics matter - it's called metaphor) you may not need much "how." Cos most people (especially the average wargamer) will have a fair idea of who is fighting who in WW2, and why. And they probably have a fair idea of what tactics will work, too. You probably don't need a lot of background if the topic is familiar and the metaphor (game mechanics/results match theme) works.
For more fantastical settings, you probably need more orientation/background; but what is actually needed? We know Cygnar and Khador are fighting. Do we need a series of maps of their countries topography? Are we 'exhaustively surveying a place that does not exist?' Do I really need a list of all engine brand-names in Battletech to have fun firing lasers at giant robots? It's indulgence on the part of the rules writer. Do they think their game universe is worth "dedication and lifelong study?" The Infinity guys (who admittedly are RPG fans first and foremost) are making a fantasy game (Warcrow). They obviously are passionate nerds but reading their design posts made me roll my eyes so hard I'm crosseyed. I really need to know the Inauguration of New Doctors for the Hegenomy of Embersig? To play a game where warbands hack each other up? This is The Great Clumping Foot of Nerdism. (Bonus irony points for them going to all this hassle, explaining their onerous worldbuilding - yet churning out mostly generic elf, dwarf, human factions)
Show Don't Tell - how do you do it for Wargames?
My daughter loves to write stories and has a great descriptive vocab and solid dialogue (for a kid.) However she loves to describe names, friends, places in exhaustive detail. When she shares her story:
"Excellent expressive words here, good dialogue here... but..." I pause.
"Show, don't tell?" she finishes.
Carnevale did a great job drawing an atmospheric, menacing Venice with Cthulhu, mad scientists and vampires, and heretic witch hunters. It did that well. It inspired me to paint many miniatures, and create custom warbands and terrain - it got me playing - success! ....But took 150 pages to do that.
Turnip 28 (Napoleonic horror with root vegetables - yes you heard correctly) rules were found on a free patreon after reading a Goonhamer article. I visited his artstation and found some more pics on another website. I probably viewed a few dozen pics all told, and read a few pages of text.
I'd say they created comparable atmosphere. Even if Carnevale did a better job, it took 20x more effort to get a similar result. 150 pages of background reading? Placed before the actual rules?
Show Don't tell means avoiding description (lots of exposition), you don't tell the reader outright, but allow readers to infer. You allow them to paint a picture using their imagination.
"Did you sleep last night? You look shot." <-show, infer, appeal to senses
Fred was tired. <- tell.
So how do we do this in a wargame?
The tell you need to avoid is obvious. Pages and pages detailing each and every last detail of each faction, technology, map, magic system. Anything more than a paragraph, that is not directly linked to playing the game (actual rules) I'd scrutinize very closely.
You can infer a lot from just the names and types of gear. "Flechette gun" vs "shotgun" I infer the game is sci fi. "Uplink node" vs "Sacred Crucible" gives you an idea of the genre without even looking at the cover. Renaming of stats into "Bashin" Shootin" "Guts" in custom way (much as it annoy me) can transmit info of the game theme (is this an orc game?). This is an example of how little things can transmit a 'feel.' (Aside: I wonder why rulebooks don't include more comic-styling, text boxes etc (which would allow more links to visuals) vs uninterrupted walls of text *cough* En Garde! *cough*)
For authors, to "show not tell," writers recommend appealling to senses (describe what the character sees, tastes, hears, smells etc) - in wargames, it's obviously all about what you see.
In a wargame, the "show" is obviously a focus on art, minis and style. It doesn't have to be done with elaborate artbooks (Infinity) or glossy magazines (40K) or amazing tabletop displays. Cool eye candy minis help - but are not essential.
Take "Space Weirdos" and Forbidden Psalm. I bet people have bought those books and built warbands and played - purely on some hipster artstyle and font that gave them a 'vibe.' I personally found neither the vibe nor gameplay of either appealed; but they are a great example of showing not telling - maximum 'feel' with minimum effort.
What are some of the tools (usually visual) that a rules writer has to engage readers in his background/world without reams of text? How do you 'show' and not 'tell?'
It's late, and I haven't really got a final conclusion here; everyone is going to have their own opinion on what is enough or too much background/lore/fluff. I guess I can do a TL:DR looking over all my current thoughts:
-World building/lore/shiny is probably the main hook into a game/reason to play; more than mechanics/rules; it's very important
-While lore/background is a main stimulus to players; too much world building can harm imagination/creativity; when the map is filled in, you can't imagine what might be in the blank spot
-World building is often self indulgent, unnecessary, and (in wargames) nearly always badly written: for the writers benefit, not the reader
-While RPGs might need detailed background info, wargames will need a lot less
-Show Don't Tell: convey the background/lore with as little text as possible (explore methods?)
-Pictures (artwork/visual elements/minis etc) do say 1000 words