I'd have no qualms taking Braun in the early second round. I'd give the edge to Johan over Braun and perhaps Soriano over him in a redraft, but quite frankly, I'd seriously mull over taking the chance on Braun over Crawford and Sizemore, two young, emerging talents who have already proven their mettle with a few strong consecutive seasons. I'd surely take him over the likes of Vlad and Beltran.
As for a regression, it's easy to pick on his average regressing. Braun strikes out a little too much than what his high average indicated and thus, in the second half, it had fallen back some. I expect Braun to be more of a .290-300 hitter. Braun won't hit at the meteoric pace as he did in '07 (you're talking about 48 HR and 121 RBI roughly), but I think he can legitimately hit .300 BA/100 R/30 HR/100 RBI/15 SB with possibly the prospects of improving that in the near future. However, the idea that Braun could've had a a career year in his rookie campaign could be disconcerting enough to say you go with the safer pick here (Crawford, Sizemore, maybe even Vlad or Beltran).