I guess to keep this list short, I'm just going to focus on the players I was critical of that actually turned into quality NFL players. There are of course plenty of players I loved who didn't pan out like I hoped they might, but that's something you expect a certain percentage of. Even elite GMs might bat .300 in this regard. A few players that have really surprised me in the NFL, in a good way:
Liuget was a lesson in sample size. 3-tech DT is a position that is notoriously inconsistent game to game. I only saw two games of Liuget and in both he looked the part physically but simply didn't generate pressure. I remember Snohomie being really high on Liuget, I should have watched more games than I did. I thought Liuget would be terrible and I was praying we'd avoid him. He got off to a rough start in 2011, but in 2012 he emerged as one of the better 3-tech / 5-tech hybrids in the game.
I was half right, half wrong about Dalton. I hated how Dalton was a pure 1 read QB who benefited from a weak schedule. But I liked his cocksure personality and his deceptive mobility. Early on I thought Dalton was a day 3 pick, though near the end I began to understand why some where giving him 1st round hype. Dalton is not an "intangibles" QB, but something about him made me think he'd over-achieve. I still thought he was a terrible pick in the early 2nd round though.
Yet so far, that's actually looked like a solid investment. Dalton had a better rookie year than I thought he would (meaning, he was non-horrible), and he showed real signs of progress at times during his 2nd season. He's finally got a decent RB that's worth handing off to in Bernard, and I really like his new addition at TE, Eifert. If Sanu and Hamilton can click, they might actually have a WR corps beyond AJ Green. You are starting to hear the beginnings of Super Bowl whispers for Cincy now, and that was unthinkable for an Andy Dalton team a couple years ago.
Quite possibly the worst prospect I have ever studied that carried top 10 hype at any point. Super slow, played out of control, a penalty machine, and dumb as a pile of rocks. Lacked character too. And Cincy got 100+ tackles out of him last year. Wut?
Solder was a more extreme Breno Giacomini in college. He was a face melter in the run game, but could be Ashworth-helpless against competent edge rushers. I didn't think he had the lateral ability to play tackle in the NFL, and he was perhaps too tall to play inside. Ironically, Solder turned into a top shelf pass protector immediately in the NFL, and is now among the games better tackles.
People talk about Wrights long arms, but what they don't talk about as much are his long legs, which made him look like a stiff mover in his college game tape. I thought Wright was a near certain whiff during the 2011 draft, similar to how I felt when they took Chris Harper a couple years later. His problems were glaring, his positives took digging. Well, Wright has looked more fluid as a runner in the NFL and while he's still a very average linebacker in most situations, he can actually be very nice at the LOS in run defense. He hasn't been amazing for us, but he's a lot better than I was expecting him to be, and I think we still haven't seen the best out of him yet, though I doubt he'll give us a peak performance at WILL which plays away from his strengths.
I had a hunch RG3 would succeed, but I thought he was insanely over-rated before the 2012 draft. I compared his mechanics to a spear chucking cave man, I noted that he played in an up tempo offense that erased defenses, and that he rarely had to look beyond his first read. He also couldn't stay healthy for very long, and had an alarmingly skinny frame with knees that buckled as he ran. I thought that with time, RG3 would become another Randall Cunningham, but I figured it would take roughly as long as it did for Michael Vick. Instead, he reached a higher level than I thought possible and did it immediately. He also tidied up his mechanics and showed real progress at checking reads. If he can protect his body, he's going to (continue to) be a superstar.
At Arizona, Foles was the definition of being a product of the system. He put up very strong numbers against mediocre Pac-12 defenses despite being lead footed, exclusively pre-snap read oriented (with a ton of Jimmy Clausen / Charlie Weis type bubble screens), possessing a mediocre arm, and showing close to zero improvisation skills. He was the definition of mechanical, like Andy Dalton minus the sneaky mobility.
It's still early, but I think Foles is going to be alright in the NFL. He's put up some very strong preseason performances in the last two seasons. I watched his 52.6 passer rating game against Carolina and came away impressed despite his low rating. He was checking reads with ease and at times looked unstoppable, but killed his numbers by Favre'ing a bad pass in the red zone after a botched snap.
Sorenson had the worst game I've ever scouted, when I watched him earlier this year. Anything a QB can do horribly wrong, he was doing it. He was Inaccurate, overthrowing, zero poise, WTF interceptions, low YPA, low completion numbers, not flashing QB skills, etc. It was so bad that I did something I've never done before or since: I made up my mind on him after just one game and passed on the chance to watch some of his other offerings. I figured that if a guy was even capable of looking worse than Mark Sanchez on a bad day, there's no way he'd be worth a second look, especially for a guy playing for what amounted to a community college.
It's still early, but Sorenson has nearly a 120 passer rating in two preseason games against very tough defenses (SEA, CHI), at least one of which has terrific depth (ours). Against us he was checking reads, making perfect throws and moving to extend plays for completions. He looked like a pro-bowl QB, and that was in his very first preseason game. It reminded me of watching a then anonymous Tony Romo cut our team to pieces in the preseason way back in the mid-00s. I came away from that game convinced that Romo was the real deal, and I lean that way after watching the skills and results that Sorenson flashed, too.