Was Betts a cancer or did he just have motivation issues?
Just reading the articles and listening to Damon Benning's comments at the time it appears to me the biggest issue with the Betts situation was Frost's handling of it.
It sounded like Betts should have just been suspended for a bit for his behavior but Frost handled it weakly. Frost kept allowing him on the team after Betts was basically being a bad teammate (IIRC lazy at practice, late to practice, I think missed practices, etc). Benning said at the time that Frost's lack of strong leadership handling that situation was bad for his teammates and bad for Betts himself.
When Mickey came along he basically had to pick up the pieces and (correctly) say "this can't go in anymore" and then Betts immediately left the team.
I think Betts would probably benefit from the strong structure and leadership that will be in place in the Rhule regime.