Some of the rumored stuff for zerg are really, really cool imo. One rumor is that overlords will be faster overall, losing speed when they poop creep which they can do while moving now.(still need a lair and overlords will still have the speed increase)
Honestly i cant say any of this is true but all i can do is hope, this will make zerg a more aggressive race in my opinion, you'll be able to do quick counter attacks even with hydras. I've been completely forgoing them because of they're slowness of creep. Roaches lings and mutas are really the only great fast units(not counting ultras in nydus) =/