I saw the "Hydralisk: Stab or Spit" topic and thought up an idea. Through gameplay and cinematics, it looks like they can do both. What about being able to choose wether Hydralisks spit or stab? It could be like the Battlecruiser upgrades. Just a thought.
I'd say the best way of this is not of the combat-fodder type zerg units (lings/hydra class)...but Overlords. Now bear with me, but having overlords to be able to upgrade abilities individually (reveal) or having some special "aura" would not be unreasonable. Overlords control the zerg army and it would make sense that the zerg combat units are more powerful when overlords are in the vicinity(their contorl is strongest then). Having speed auras, life regen aura, armour aura, attack speed aura, damage aura, even life-steal aura on different overlord would bring a new level of zerg game play, where you sacrifice your smaller units, and try to protect your overlords for the good of the army.
