Updated HUD:
I find the HUD to be somewhat confusing at times. I'm use to it now, but it would be nice if some areas were updated, making it more understandable and easy to read.
Sounds:
I believe that this is a work in progress, but the berserkers jumping sound sounds like a dog barking, and I find that it is very loud. It's like if you are 50 metres away, and 1 metre away, its the same decible of sound. Also, are radio calls something that could be included?
Animations:
I think the swiping animation (attacking animation) by the aliens needs to be improved. Also, if you are an alien, you should be able to see you're arms/claws/whatever attack/swing (more so if you are a maruader or larger alien).
Speed
Maybe the speed of some alens or humans can be altered?
Upgraded Models
I know this is in progress, but a lot of weapons still need upgrading, as well as things like the jetpack? juggernaught suit, and basically anything from tremulous.
Map Upgrades
If I can get permission from the creators of old tremulous maps, I can update them :)
Acid Tube Range
I believe Acid tubes range should be extended for fairness.
Buildable Upgrades
Maybe we can use power or money to upgrade buildables such as turrets, which may increase their range, or damage (same goes for acid tubes).
I also suggested that floor Mines be added :)
Maybe the reactor (or aliens overmind) have upgrades giving them more health, allowing them to attack and do higher damage.
Sorry if I have suggested things that are already under development, but yeah, this is my wishlist.