This list might be for mostly Aliens, as thats who I have the most experince with, and because they naturally need more balance being that they are very different from every other FPS out there (while the humans are not).
Alien Structures:
1. Barracade- Good concept, bad presentation. First of all, this structure isnt as good because it also blocks Alien's movements as well as human's. What comes to mind is someone like how the forcefields in Tribes work, the barricade should allow Aliens to "shift" (or just have the vines "move out of the way") through them at 1/4 of their full speed, while they completely block human players.
Also, the fact that it doesnt do too well at barracading in the first place (unless its in a small area) doesnt help either. How about a sort of "wall-placing" mechanism (such as, holding down the place button and draging it will make a wall of barracades)? Or have it so when placing a barracade, you can place up to 3-5 in a row, but if you want pressing the cancel key while a barracade was already placed will cancel any extra barracades.
Also, because they dont really fire anything other than block a path, I dont think that barracades should have to be within a certain area of the Overmind, they should be able to be placed anywhere, like the eggs. If this is already how it works, then disregard this suggestion.
If you dont have it so you can click+drag (or similar) a wall of barracades, then atleast have it so it doesnt count as the overminds build limit, but there should be a limit of total barracades on map (to prevent spam of barracades). After all, the barracade is nothing more than a root that has been planted, i dont see why it would need an overmind to operate fully (you should still need an overmind to build them though, just not be part of the build limit). Such as, how the repeaters work for the Humans.
2. Dretches- not deadly enough? I would think 4-5 bites on a human with just light armor for such a "leathal" bite (according to the manual) is alittle much. It should take 1-2 bites on a human with no armor, 2-3 with light armor, 3-4 with armor+helmit, and 6-7 with a human with battlesuit (because the battlesuit is actually heavy duty armor). Right now its also pretty useless against Stage 3, as since everyone either jetpacks or battlsuits, and its impossibly hard to kill guys with battlesuits (i think i counted around 13-15 bites, might of been using the medipack though), especially against a lucifer cannon. Killing a guy with a dretch is more or less luck at Stage 3. Luck that the guy your biting is an idiot, and luck that he might be already damaged badly. I guess its more of a support unit anyways this late in game, but you get my point.
3. What does the granger's spit do? Right now i havent found any real good use for it. If it momentarily paralyzed the enemy (2-3 second normal, 1-2 seconds if Battlesuit), it might be more usefull. Whats it do?
Well, i think I might have more suggestions later on relating to the gameplay. I havent played the game to the fullest extent, and I'm running out of time
