Gallery was rated as a top 5 talent. He would have been taken higher than Barron. Barron is equal to Gallery (maybe superior) in athletic terms, but Gallery showed a better and more consistent ability to put it all together (as well as showing more passion). Obviously I'm talking about Gallery as he appeared coming out of college. In hindsight, after seeing his rookie season, he may have been overrated.
Shawn Andrews was a top 10 talent but slipped because of concerns on his pass protection ability and due to team needs. However, Barron would have gone higher than Andrews because Barron is a LT where as Andrews is a RT (currently playing guard, but was projected at - and will eventually play - RT). He was known coming out as a smash mouth road grader. He was a player that had much less downside than Barron. However, again, LT's are much more valuable and it is VERY rare (can't remember the last one) for a guy projected to play Guard or Right Tackle to be taken top 15. So that is why Barron would have been picked higher -two different type of Linemen that really can't be compared to eachother, apples to oranges.
Vernon Carey was rated as a VERY late 1st/Early 2nd type player. He had alot of question marks. Came into UM very highly touted but was always inconsistent. When he got his weight in check, he could dominate, but most of the time he was too inconsistent. While he had played RT some at UM, he projected into a Guard/potential RT prospect. Too many question marks and he had yet to really put it together at the college level let alone show that he was ready for the pro level. The idea was that he had alot of raw potential that, with a couple years of good coaching, could possibly turn into a VERY good pro in the mold of Larry Allen. I don't think anyone had him going before the very late 20's in mock drafts. Wanny reached pretty high once Andrews was off the board. Vernon was the type of player that should have been taken in the mid 2nd (IMO) and allowed to develop. He has a ton of upside but a ton of downside which is why he's not a 1st round talent. Similar to Chris Henry from this year in that there are alot of question marks and he'll take time but if he hits he hits big (you generally don't use a 1st on a guy like that). Barron would be taken far ahead of Carey last year, this year or any year. Moral of the story - be happy Wanny is gone.
That's not to say Carey won't develop into a Pro Bowl O-Lineman (I don't think it will be at LT). But even if he does, it was still stupid to take a guy like that so high. It's the equivalent of taking Matt Jones this year with a top 5 pick because of his upside. I think it's dumb even if he does turn out to be a pro bowler (now late 1st/early 2nd is fine because Matt has "once in a lifetime" type numbers so he's worth a bit more of a gamble than Carey who, again I would have valued as a mid 2nd.)
Sorry for the lengthy response.