I agree with Norf about the battlesuit. After you get the battlesuit, there's a low chance that you'll never be unable to get another one. Soldiers are pretty much free credits for battlesuits, and they can stay out longer because of this. Im not saying battlesuit is overpowered, but that its just gained way too early. If its gained that early, perhaps it needs to be toned down, such as hydra being able to stick it (however, the person would be able to turn completely around) etc. A higher cost is a must then, and so forth. It would just make alot more sense to put it as a later upgrade, which, as norf has explained, would balance out the defensive upgrades for the humans. Light armor -> Helmet -> Battlesuit instead of Light armor -> helmet + battlesuit -> nothing.
Also, I was thinking that maybe SOME aliens might be more resistant to "Energy weapons" (lucifer, pulse, las, painsaw etc.) than others. Perhaps Chimera or something to give a little incentive to use that class perhaps when there's alot of humans which are lasgunning or even near the end when humans have lucifer cannons. Its not that I find those weapons too strong, but it gives a little edge. Usually me and norf are unstoppable when we load up our weapons and go (me = lasgun, norf = pain saw).
Flamethrower I find as an incapable weapon for most situations. Infact, the only situation I find it suitable is killing a few soldiers that are attacking you. You can wave it around and take out multiple soldiers that the other weapons cannot do. However, everything else just isnt worth it. I was thinking hard. Maybe this gun is good for its price? I checked the price and found it very expensive. Nope. Maybe, I thought, it was good at killing alien structures? I tried using it to take out structures and eggs. I wasted almost all of my ammo shooting one egg. Also it takes alot of ammo to kill defensive structures. No, not alien structures. So, if its not good for that, it HAS to be good for defense, right? Then I tried using it defensively. No, it doesnt have enough range to be effective defense. Plus, if you are defending the base, you'll probably scorch something important. X there too. I was starting to get desperate: perhaps its good on higher alien classes? Way wrong there. Well, its fire, and fire is usually really bright, so perhaps it can light up dark areas, I was pondering. Suprisingly, it wasn't good for that either. Which leads me to a question for the Dev Team: what CAN the flamethrower be used for?
As to norf's suggestion about ammo, I thought maybe a purchasable Ammo pack could work. Same concept as the Battery pack, and I'm sure its probably been said before, but Norf is right, it would give humans a better reason to attack than defend.