From what I saw, I really thought he showed flashes of being a very good slot CB. We'll see. Though, your comment about scheme etc. suggests bad play is not always a CB's fault--Florence sure took a lot of criticism about his play too.
Re, the positions of need. I have similar thoughts about WR. Take away Parrish, and it's the same WR crew that scored a lot of points when healthy. While I think they could get by at CB and WR, I won't be disappointed by a R1 pick up at either position, though I lean CB over WR.
OT is currently the weakest spot on the team. I hope they re-sign Bell, so at least they have options and experience.
I think they can find LBs in later rounds who fit their scheme--since most teams are now looking for 3-4 LBs. I also posted about Moats and McKillop as a couple of talented backups to 2/3 LB positions--however they do have ?s
TE is riddle wrapped in an enigma. Yes, they can use more talent and competition, but how important is the position in Gailey's O? That said, I'm sure he'd like the option of a stud receiving TE with speed who can line up in a spread formation.
At any rate, I think this draft should put them to a good place across the roster.