Destroyable spawnpoints in the hive with weak alien hordes respawning (almost) immediately after dying.
The marines objective would be to destroy the spawnoints in the hive instead of killing a limited number of aliens.
Benefits (How this will benefit the server and game as a whole):
I think this would fix the most serious shortcomings as of now, like marine camping, bored marines (eg. when they are just sitting in the FOB and nothing comes) and would make more people to play aliens as they don't have to wait to respawn, can be aggressive all the time and act more like a mindless creature of the movie.
Details (Description of how you think this would work, the benefits, etc):
Spawning
I think aliens should have a limited number of buildings working as spawnpoints. These would represent the nested colonists. These could be placed by the queen at round start. These would be an infinite supply for weak aliens (call it T0). After dying an alien player would (almost) instantly respawn as a T0. Dying as T0 would cost almost nothing. This would create waves of weak aliens attacking constantly. Which is fun for marines because they are not sitting in the FOB doing nothing. Also more fun for cargo because they really need to deliver ammos on time. And it gives the overrun feeling of the movie. The marines could win only by destroying these spawnpoints. No more reason for camping as marines.
Evolving
This one could have a lot of shape, I think two things that can be used are larvas that bursted from marines and jelly.
One possibility follows.
Classes and evolutions (sentinel is missed, icons could be reused as T0). Classes may need nerf. Eg. spit is not a good idea for the weak T0.
T0 T1 T2 drone -> carrier, hivelord sentinel -> spitter -> praetorian, boiler hunter -> ravager runner -> crusherTo get to a higher class you need jelly (T0 to T2 is two jelly not just one like now) or if the larva came from a marine you start as T1 already. Jelly could be much more limited. (Now everyone can get one easily especially if sharing plasma.) This would gave additional choices to the queen: should I spend the jelly to get T1-s or should I wait and try to get a couple marines and spend the jelly on T2-s.
There is the problem that the ones who die the most would most probably spawn as the T1 from the marine likely wasting it. I don't know an elegant solution to that.