The Worst Heisman Winners to Ever Play in the NFL is the title of the article.
Very different than "Worst Heisman winners"
Thread title sounds like the most undeserving Heisman winners. That would be a completely different list than Heisman winners that turned out to be NFL busts.
Heisman voting has changed. It used to be a mix of positions, mostly QB, WR, and RB, with an occasional defensive player. Now they elect a quarterback every fucking year. Mark Ingram and Reggie Bush are the only non-quarterbacks to win in this century.
To answer your question, in the last 10 years, the only Heisman winner I would have definitely taken top 10 overall
at the time would have been Cam Newton. I was never that high on Leinert, RGIII, Bradford, or any of the other Heisman winners as QB prospects (and I'm also not high on Winston or Mariotta this year). I
might have taken Bush or Ingram top ten overall, but that was back when it was still trendy to use high draft picks on running backs. In retrospect, taking them that high would have been a bad move.
EDIT: Forgot about Bush