1) adv basilisk: Adv basilisks, don't differ much from normal basilisks than with bigger health and the poison cloud. Those things I do think give the title advanced to basilisk. And who said that basilisks are bad? I've killed sooo many humans with it's grapple that I cannot even image that I've done it. Basilisks are better aliens than many have thought, their grapple is incredibly useful. If a human scouts alone, it's almost a free kill. This excludes people with the battlesuit of course.
2) adv dragoons: Mess with them.
3) trappers: Useful defense, should just be located so that when humans shoot the acid pots down, then the trapper has time to grapple.
4) flamethrowers: Agreed, more damage to self and should shoot more further.
5) painsaw: Only for experienced players.

6) luci cannon: Could be interesting, if it just wouldn't be 'high-pitch' so that it doesn't hurt ears everytime you charge a lucifer cannon.
7) Bullets: I think the big reason is the delay between of your computer/connection and the server. Atleast I have no problem at all with rifle.
8 ) Stage 4: Now this is where you need to play as a team, the end game. Usually if humans just camp, they end up dead because of it. You do know that few tyrants and adv goons do bad things?

9) human turrets: I know the human base camping is annoying, but it is easily crushed if something breaks. More alternative turrets like a "Mass Driver Turret" (with reduced power [otherwise it's too good] ) would be interesting.
10) jetpacks: These things have already plans on. They will have energy.
Suggestion: The thing when human jumps repeatedly 3 times and goes 'exhausted'... should be enabled to jetpacks after shooting with mass driver or lucifer.
11) gliders: Not a good idea, Have you tried to jump with adv goonie?
You'll catch even the jetties in atcs with adv goon. Alternative suggestion for this I'd add would be that adv grangers wouldn't be that fat, but more speed and agile look. - But no flying aliens.

12) helmets: Realism. But to think is as true realistic opinion, those helmets wouldn't break after few head blows. A bike helmet doesn't break after you fall few times does it? It's maybe damaged but not broken. But IMO, these things should have some tweaks. (And yes I'm still whining about invisibility for non-moving stretches)
13) damage: Aliens are pretty easy to kill with the weapons that exist now. If you just load a full charge lucifer into a tyrant, that tyrant will be dead meat. I've experienced it several times with a full health tyrant. As well for other human weapons, aliens are pretty easy kills.
Conclusion: Imho, you need more experience in playing Tremulous with both humans and aliens because the gameplay is quite balanced. But I also want to see new material on both sides... more options. But after all, much depends on the players. As for example, AFK players aren't much useful are they? Hehe, yeah they aren't and that could be sometimes the reason to defeat. This is team-based game, and that's what it is. Tremulous ftw.