I am not entirelly sure how your examples relate to Piratez; if they do not, you're just saying obvious things. Well, maybe not so obvious to everyone, but obvious to me, because striking balance between discouraging pathological exploits (or you can cynically name it, game experience I do not want to happen as the developer) used by "best" players while not fucking players who just want to have fun, took many many iterations to arrive at this point, and it is an ongoing process still. As for "top" players I have no idea whom you even mean, because that depends on your definition.
Enemy having firepower advantage - this is certainly not true for the most part in XPZ, however does happen in hard missions - especially if you don't expect what will happen and not escalate your means of violence proportionally, or, so to speak, break out the big guns you don't normally use (which is deresively called "gear check", as if getting better gear was not a matter of player's strategy). As for advantage of player in intelligence - yes, one example is that player can abuse automatic doors and AI can't. It doesn't however take much intelligence to do so.
If you think camo is useless because of the fact enemy can spot you - yes, if you hit a "spotter" enemy, communication does get relayed, and your unit stays spotted for a few turns, but I play a lot of nightfighting with the use of camo, and it surely works - just requires, uhm, intelligence to use. The difference is, using camo and darkness is no longer overkill, you need to keep some focus to your formation and possiblity of getting spotted, also some contingencies for the case enemies might still be able to shoot at you (however inaccurately) and hit, instead of just forming firing line, lighting enemy up and keep mashing "end turn" until they all die. You might say, I don't consider "never get your soldiers hurt" as "best gameplay". That is not to say you're in any way worse for ignoring camo - you make your own rules, and play your way as Player One, of course - but dismissing the whole concept while knowing nothing about it is rude.
Yes, my hands are largely tied, but I do propose improvements to the coders, and some of them get implemented. Like the sniper-spotter system ("AI LoS cheat") and no-LoS firing penalty, as well as CQC system, to name just a few things.
I am sorry if my replies seem harsh, but I have to deal with frustrated players on almost daily basis, and with real psychopaths at least twice a year.