Let's look at the remainder of the 1st round to see who the Hawks might have taken.
A. J. Jenkins
Not exactly a list of breakout players.
Chandler Jones, chosen by New England at #25, is going to be a star and would have been a much better pick, but that's hindsight (even though I was advocating for Chandler Jones at the time.) You are generally right that there wasn't a lot to choose from. Irvin is not nearly as good as I would hope a #15 pick would be -- he probably won't start even if he is healthy -- but given what was available, I can't complain too much.
Bruce Irvin is, of course, a great athlete, along with being a good guy who takes his craft seriously and works hard to improve. Fans tend to get infatuated with great athletes and overrate them. The question yet to be answered is, "Can he play football?" It took Malcolm Smith and Byron Maxwell a while to make it, so there is still a good chance that he could break through.
The eight sacks his rookie year were, in my opinion, an aberration. They occurred mostly in home games where there was ridiculous crowd noise and the offense was confused. He had very few tackles outside of the sacks (3 solo tackles for the season and a few more assists), but he was in only for passing plays. Most of his sacks were when the plays broke down and the quarterbacks had to move and weren't expecting someone that fast to run them down that quickly. Usually, he did not penetrate directly to the QB. That is why he only had four QB hurries for the entire season. Once the league figured out that all he did was run fast around the outside, he was dominated. He had *one* sack his last eight games. He was totally exposed in the playoff game against Atlanta when Clemons was out.
I have very strong supporting evidence on my contention that he was not the pass rusher his numbers indicated his rookie year: HE WAS REMOVED FROM THAT ROLE THE NEXT YEAR.
As a linebacker, he was adequate -- at best. After he served his four game suspension, he started every game except the Super Bowl. He seemed decent at first but like in his rookie season, he disappeared towards the end. He contributions as a linebacker were, imo, minimal. The fact that he was replaced as a starter by Malcolm Smith in the Super Bowl and that the defense played the best it's ever played says a lot. There is competition, but Malcolm Smith -- who was unbelievable the last two games -- is the presumptive starter going into the season.
Bruce Irvin still has a lot of potential. He is incredibly fast for a front seven player and has put on weight. Hopefully, he has gained some power with that weight. Ken Norton, Travis Jones and Dan Quinn are great teachers, and Irving is a hard worker, so he will surely improve. Both Quinn and Norton said that along with playing linebacker, Irvin would play at pass rushing DE more this next season, as he did in rookie year. I think this is his best position and the position that he wants to play. With added weight and power, better technique and more moves, I don't think he will get dominated like he did the end of his rookie season.
I don't think the coaches would mind that much if Bruce Irvin was stashed on the PUP list at the beginning of the season. With Korey Toomer and Kevin Pierre-Louis (I also like Mike Taylor for the practice squad) added to a line-backing crew that has everyone back, it would give them a chance to keep one more player to evaluate.