Well you can't have it both, so if we want something new and fresh, some old unit should have to be removed, i would personly remove the Hydra ( even though its one of the most recognizable zerg units, and peoples favorite , including myne), you could easily replace the Hydra with
2 new units, since the hydra has so many roles, and you could finaly give the roach the place it needs. But i doubt that will happen, since people would freak out if the hydra would be removed

, so the only other way is to ad a new unit, that would replace the hydra lategame( since they suck lategame), hence my tentacle attacking unit suggestion
