Aliens just need more hard counters to things. HA should not be Oh crap HA gg. We were talking about this in IRC, aliens need uber hive 3 abilities. Charge should kill A3 LA marines in 1 hit. Unless the marines are very good(And if they are very good, why did the aliens get 3 hives in the first place?) they can't recover from hive 3.
Oh and diablus, since you start out with 25 res, all you need to go fade is 25 more, that comes preaty fast, faster if you skulk and kill a lot.