Been a few rumours about Choco over the years in that regard. Not necessarily even him doing it on purpose, but he's competitive, can overstep boundaries, and occasionally sees slights/enemies that aren't actually there.In light of the fact that Choco threw his hat in the ring for the main coaching gig but wasn't even short listed, I reckon that he'd probably be spending a fair portion of his time white-anting Noble.
If you don't have him in the top job then you'd want to have him tightly under control. Personally I was really disappointed that we supposedly didn't even give him a second look for the senior coaching gig as the fire still burns there for him.
As for Roos vs Choco, I'd say it's apples versus oranges. Roos probably is quite capable in playing that auditoresque mentor role at various levels of the club (even if it costs a kings ransom), but choco is clearly very capable when it comes to player development.