I have a few general thoughts about improvements to game play.
More casting. Some units have the D to cast a spell (of sorts). I think it would be interesting to see more of this, with bufs/nerfs or different effects that you could play on the battlefield. Would be very interesting. I think a "warp" or some kind of "phase jump" would be killer for units to breach up walls. We have the single capture rover (that I know of), but what if there was more of a hacking sort of thing.
More upgrades (morphs). Right now only a few units seem to have upgrade abilities, and are somewhat limited. Imagine a bertha could morph to increase fire rate, maybe at the expense of range, or maybe split the projectile to cover a wider area. Perhaps the commander can have a third weapon, or a fourth, or grow to become a dante's boss, with a cannon from the spider riot unit.
Hunker. It seems that if a unit can hunker, its range and accuracy should increase while hunkered. In the case of the crab, it should also take less damage while not on the move. Possibly this applies to other units as well, though I usually play spider. Solar panels seem to hunker, but I can imagine more static units also. Hunker might apply to a sniper unit as well, the notion that you can improve range and accuracy perhaps at the expense of mobility in some way.
Guard positions. I really like to play where your factory sends all units to guard or patrol.. I can't quite tell, but it seem that if the guarded unit is attacked, then the units guarding move to attack. If I'm not right about that, then it something I think would be very interesting. For example, If the guarded unit is mobile, a "forward" guard might put all units out front of the target path. Perhaps this changes for the type of unit that is doing the guarding. Perhaps a circle around the unit as it moves would also be an interesting formation. Flying V?
Patrol a mobile unit. Similar to the guard idea, if a mobile unit could be patrolled, then the patrol point is constantly moving. Same rules about resource collection, repair and attack, but just from a mobile position, or between two positions. Would add some nice mechanics I think.
Patrol line adjustments. For a patrol that has already been laid down, sometimes I want to adjust it.
Also learning how to dev on the game. I write software all day, and it would be fun to design units or game features, but I find the barrier to entry a little too high to just get something up for PR in an evening or two, and time is precious. I think it would be neat of folks made a video or docs on how to bring new things to the game. Help bring on new developers. I've seen some of what is available, but I need to "cross the chasm", so to speak, and additional resources would get me there quicker.
I really love the game. I didn't read all the posts in this thread, but it seemed the most appropriate place to post. I'll read what others have mentioned before this as well. If my ideas are off-base or that I'm trying to make a different game, feel free to let me know. Just some thoughts after playing for many hours, playing PA before this, and then TA before that when I was just a small fry.
Clearly games like Mechbellum are taking inspiration from zero-k units, and I see a little room for this game to take a bit of inspiration from other games as well. Some of those units are pretty neat. Planetary Annihilation is neat only because its a planet and not just a map. That game doesn't play nearly as well, but a few concepts are interesting. Starcraft2 casting is super fun for the squad management and intense fighting. Tabbing through units to select the cast and then tabbing to the next cast can be exhilarating.
Anyway, really happy to have found this game a few years ago.
Cheers.