Well, I don't know the first thing about modding and such, but i thought it'd be extremely cool to implement a few new weapons or a class or two to trem. The first thing i thought about adding or more, replacing the psaw with would be an energy sword (light sabre w/e). cause not only would it serve an aesthetic purpose but also a practical functionality with having a "one-hit-at-a-time" weapon as opposed to the current Psaw that you can hold down forever, which is cheap and yet at the same time flawed, range wise, as you have to be touching the enemy to do damage =/ one thing i never liked about psaw. anyway, having a sword with a 3-4ft approximate range and a one hit instead of constant fire would be nice as it allows you to hit from a bit further away while only dealing single strikes with decent damage say 50-75 or possibly make it stronger with each stage like S1 50-75 S2 75-100 S3 100-150 or somewhere in those ranges while changing the color each stage so it's apparent what stage the hummies are so you don't get a "150 damage surprise". and yeah, the single hits would be funner too because you'd have to time strikes strategically (in the case of a dretch or basi flying at you) instead of running in like an idiot with the trigger held. This also makes it a bit funner and less cheap for the aliens too because it becomes harder to destroy structures in mere seconds with it (I have never liked the "run in and PSAW the OM" strategy don't really consider it a strategy =/ )
anyway, next thing I thought about was maybe making a better rifle for S2-S3, cause I mean, the rifle is actually one of my favourite weapons, but it's just too weak ya know? so I thought it'd be nice to make a better rifle for S2+ that had better damage, and better accuracy and a bigger clip, so it'd be a fun-to-use projectile weapon that isn't horribly inaccurate *ahem* (chaingun), for those of use that love watching shells fly out of the chamber and hearing the satisfying rattle of a projectile weapon and the always great sound of the bullet meets concrete noise.
I also thought about maybe adding (or replacing the MD with) a sort of Beam-fire energy weapon (like the Spartan laser or the covenant beam rifle from halo 3), because i don't know about you but i like to see a straight line from my gun to my target, makes it feel more accurate i guess O.o?
and coming to the aliens, I know alot of people have wanted a flying alien for a long time to make the levels with high ceilings (rotcannon example) more fair for aliens in regards to jettards. so i thought maybe the
Scourge unit from starcraft would be cool to model it after. It'd have a close range melee attack (left click) be able to hover, shoot small, low damage projectiles at blaster Rate of fire but slightly faster projectile speed (right click), but it wouldn't lose altitude when under fire like human jet packs. I think a base HP of 75-100 is good, and then increase size and HP to 125-150 range and also add an acid cloud ability (Mouse wheel or alt) (like crop dusters =P) that would have 1 use (represented by the barb symbol like an adv goon) that would somewhere in the range of 10-25 dps and could be sustained for anywhere from 3-5 seconds before having to be recharged taking the time one goon barb takes to charge. It would fly at about the speed of a normal human run speed so it's not too hard to hit, as it's relatively small and can dodge easily due to being airbourne. this class would have to be available at S1 but cost 2 or 3 evos (i say available at s1 cause it's easier for humans to hit aliens from the ground than it is for aliens to hit humans from the ground at s1 once they get jets at s2).