What if aliens could sharpen their teeth on say alien resource towers to get a damage bonus for the first succesful bite/hit that lands on a marine or marine structure?
Perhaps it could even be that aliens need to constantly sharpen their teeth as they get blunt after a lot of chomping - but maybe the primary attack no longer uses adrenaline (cept gorges cause they have no teeth).
This would encourage aliens to guard res towers, and also to keep moving around the map.
it could even be such that the primary attack does less and less until it eventually does only about 20% damage - you could have the teeth in the skulk hud/weapon view broken so you can tell how much damage you are doing.
