You don't draft your QB of the future unless your QB of the future only has 2-3 years left.
When will all this development magically happen? Backups get almost no reps once camp is over. That is why veteran guys like Batch keep jobs for so long. He can get thrown in there on short notice and not be in over his head.
Unless the Steelers intend to trade or cut Ben within the next 2 years, the 4th round was too steep a price for a bench warmer who likely won't even dress for games.
I don't even like the QB pick in RD 4 if it was a QB i liked. Landry Jones was a QB i didn't want in any round. He's a system QB with happy feet like Gabbert. It's hard to break a QB out of that.