Cody Asche was never "highly regarded" except by starry-eyed fans. There were questions about Asche when he was drafted, and he pretty much performed to those issues. The discussion as he moved (quickly) through the minors was about how he was outperforming expectations, and whether he could continue that in the Show. He didn't, and I don't think most of us were surprised (disappointed, because we wanted him to be more than he was, yes - but not surprised).
Bohm isn't a perfect prospect, but he's a lot closer to Chase Utley - in terms of scouts' opinions of him at draft time, and in terms of his draft position (surprise, surprise) - than to Cody Asche.
I could link you to posts in our archives, from well-respected posters here, who were seriously concerned that Chase Utley wouldn't hit left-handers, and that he would be a defensive liability. Ahem.
Based on what little I've seem from scouting on Bohm, the number one negative I've seen cited is that he's "too tall" to be a good third baseman, because he's 6'5," instead of 6'3." I guess I'm just not convinced that those couple of inches really matter - I suspect that there's a certain amount of "traditionalism" encapsulated in those scouting assessments.
Time will tell.