Yeah, that's a pretty non-typical "NBA Rookie" crop in terms of age and experience. There won't be years of waiting for "upside" to pan out (see Telfair, Webster, Outlaw, Bayless, Batum.) This time next year we should have a pretty darned good idea of which of these guys are here for the long-haul. (Except for Melvin. I'm planning on being patient with that guy.)
I'd add Elliot Williams to MM's list as essentially a rookie, since he only played 149 minutes last year. Williams is 23 this year, though, so he's an older "rookie."