I'd like to see in new version of Tremulous an advanced dretch (no evos needed to evolve).
Example:
30hp instead of 25
10% more speed
10% more damage (optional)
It can be added in stage2 or stage3, as you prefer. Dretches suck too much against pulse rifles, bs and lucis
Moreover move avd goons from stage 3 to stage 2, sniping ability would balance the fight in stage 2, if you don't like this option you can add more damage points to adv granger snipe, so he can attack.
IMHO the best fight actually take place at stage 1, at stage 2 humans are stronger than aliens, at stage 3 aliens (tyrs) are stronger than humans.
Add secondary fire to pulse rifle
Add an "advanced rifle" at stage 3 (35 bullets instead of 30, more damage, secondary fire)
When om is down alien's radar should be deactivated (don't know if it's already implemented)
Prevent human camping and lasgun/pulse/luci spam
Sitting on a building should damage it (except medistation), so humans can't camp on turrets.
No idea about how to prevent spam

(maybe weapon overheating?)
To prevent deconers:
need at least 2 constructor in a team to decon reactor/om, this doesn't mean it takes 2 ppl to decon, just there must be another constructor (alive) in the team, otherwise you can't decon
the last node/egg can't be deconned, if you are moving base you must build a node in new base before deconing the last of old base.
Give to human constructors a melee attack, blaster is useless against pretty all aliens.
Sorry for my poor English :$