More weapons! Give us more weapons!!!
The MECs and genetic enhancements and whatnot sound great, but my biggest gripe with Enemy Unknown was the two weapon tiers where lasers were downright skippable with just a little forethought. I want to see more tiers, like say; traditional -> railguns -> lasers -> plasma -> quantum (or gluon, or unicorn fart or whatever), possibly with unique skills and special stats related to each of them (say, plasma weapons would be the strongest but volatile and each hit on the unit holding them would have a chance of rupturing them and causing and explosion while lasers would be the weakest weapons when it comes to damage output but silent, invisible and with infinite range, thus not giving away your position and allowing sneak attacks, just to name a few possibilities). This way weapon load-out would be actually engaging instead of sticking plasma guns on all your units ASAP and never worrying about it for the rest of the game.
I mean, they already did the balancing act with the armors when it came to raw protection versus bonus utilities, why couldn't they do the same with the weapons...?