Generator Servant is actually pretty awesome: since it's got a decent body for its price you either attack with it or bring in something bigger and still get an attack with that. Can't imagine it won't see Constructed play, definitely in Standard but also possibly in older formats if they can find the right creatures to pair with it.
the elemental is fine and makes me wounder if it is playable.
Wizards what are you smoking why are you dunbing the hive that much? really? a 5/5? this is a **** to the sliver's noble lineage ... Its like the Ret-rd-- son of the queen (I learned evolution theory with mrs. Garrison )