+diversifying the appearence of higher liveforms
in my opinion it would be beneficial to untie crag, shade and shift trees from 1,2,3 hive and let them be evolved at 1 hive. with untied lifeforms it seems like the next logical step, because the real limitation is, that every alien can only evolve 1 of them at 1 hive, 2 at 2 and so on.
this would realy spice up the game for aliens and marines.
suggested addendum: scaling evolution pres cost: 1 evolution for skulk and gorge 2pres, lerk 4, fade 6, onos 8;
this should reintroduce and widen the timeframe at which higher lifeforms appear.(i estimate a spread of about 2minutes for fades)
a player that never uses any upgrade will still get the fade at the current point, but i believe people would every now and then or maybe even allways choose one.
i think this would go nicely with the mainchange, because a skulk that has no luck with carpace is likely to try cloak, regen or silence sometime.