Let's look at some features of the PC RTS and how they would apply to tabletop wargames.
This post was inspired by "Impossible Creatures" - an old school RTS where you can create hybrid animals to attack armies of mutated enemy animals...
"Clicks per Minute"
The ability to micromanage units with relatively few sitting idle is a RTS skill. This could be simulated by having a set amount of activations; i.e. you get say 6 "actions" per turn; an action can be used to move a single unit or group of units which are bunched together. I guess the word "limited actions" kinda covers it.
This could be collecting crystals, gas, or whatever unobtanium. Often there are two resource types - a general resource (mass, such as steel to make tanks), and a rare resource for producing high tech units (unobtanium, to power fusion reactors or tesla cannons etc).
I like the resource collecting aspect; as interdicting resource collectors (harvesters) and escorting them can provide a source of small clashes and a kind of alternate victory condition - deny the enemy the resources to build or replace combat losses.
Another sort of resource is "control points" as seen in THQ's Dawn of War and Company of Heroes series; dozens of control points that can be captured and provide a stream of resources and an incentive for constant raids.
The resource management puts another layer on top of the game; and allows for base building and unit building meta-games; you basically can "build your army" during the battle, not just before it (a feature of games like Warhammer 40K).
A further thought is that resource management must be kept simple, perhaps being tracked by tokens of different colours.
Tech Levels and Research
I think researching new tech would be outside the scope of a tabletop game, but many RTS have several "tech levels" of base - for example tech 1 could be simple grunts and engineer units; tech 2 light vehicles, tech 3 advanced vehicles, and tech 4 mammoth tanks and super weapons or advanced stealth fighters etc. This "teching up" might cost resources; so you might have the choice between remaining tech 1 and making a cheap "horde" army to attack early; or sitting tight and advancing as fast as you can to tech 4 to beat the enemy down with superweapons. So "research" in a tabletop game might be simple; merely deciding which of several tech levels to stop on.
Bases & Base Building
There are usually a main "command building" which once knocked out, removes the ability to build new buildings (kinda of an "assassination" target); usually a resource-gathering centre, plus production centres for ground and air units. Sometimes there is power generators (knocking these out is another way to cripple production capacity) and base defences. There should be a balance; do you try to nibble your way through enemy defences or try to deep strike past them aiming for critical buildings and generators? Again there is a level of choice - what do you spend your resources on? Base defences? Advanced buildings? Do you eschew aerial units in order to make an overwhelming ground force?
Unit Building Metagame
Units usually have a faint paper-scissors-rock feel; a light minigun tank might easily be gunned down by a heavy assault tank; but the assault tank loses to a sniper tank destroyer which can easily be swarmed by the minigun tank...
Choosing how many of each unit should be an important part of the game. As min-maxing armies is popular out of battle (a quick google will reveal a zillion army lists for "best practice" in games like Warmachine and Warhammer; creating optimal lists is a popular pastime.)
Unit Levelling + Recon/Fog of War
RTS games sometimes have the ability to level-up units (often hero units or heavy units) which gain accuracy buffs etc as they get kills on enemy units. Another, more common feature is "fog of war" - anything not in LoS of a unit (or within their "view radius") are blacked out by the "fog of war." In games like Wargame: European Escalation recon is vital; sneaky infantry recon units can call down indirect fire while remaining hidden, or allow units into ambush range of their RPGs. They can protect valuable units from being interdicted by their counters - i.e. spot SAM batteries to protect valuable gunships, or spot hidden tank units allowing ATGMs to be wheeled into place to take them out. Having good recon should, in the least, allow you to best counter their scissors with your rock, while keeping your paper out of the way.
I'm sure there's more key points to cover here, but my wife has returned from a seminar by author Mem Fox (does anyone know Possum Magic or is it purely an iconic Aussie-only children's book?) so I'll wrap up this post and join her watching Preacher (an awesome show, btw, though not particularly similar to the comics.)
So... where is this post going?
Well, the RTS-meets-tabletop wargame is something I'm going to explore more. I'm sure there are boardgames that do something similar, but it's wargames that interest me. I know Brent Spivey did OP4S years back as a RTS homage - but it does not seem to have gotten out of beta (I did a brief review way back in 2011). I'll dig it out again - I could do another test play as I've pretty much forgotten it apart from it having a nifty activation system.
In the Delta Vector google group we looked at landships/motherships/megavehicles a few months back (you know, Ogre, or a Cylon basestar, or an Avengers heli carrier) and I'm now a proud owner of a Landcruiser Ratte in 15mm. I keep looking at it and thinking it would make a good giant mobile base factory/landship/landcarrier for 6mm mecha, and I've attached tracks to some WW2 1:700 aircraft carriers to make them into landcarriers...
I've gone with 15mm for my tank project, leaving me with many 6mm sci fi vehicles unused. I feel 6mm tanks are too small to be "main characters" but they make an affordable horde to be spawned from larger "landships" which could be the heroic units which level up.
I also think RTS might be fun with a focus on a different aspect of sci fi than usual - perhaps with nanomachines or similar.