I thought Ek & Bo butted heads. I don't know that it was ever apparent why. The murmurs included Ek's recruiting tact. I thought it was clear that of the coaching moves Bo made, only Sanders and maybe Carl was a situation where his hand was forced.
Anyway, Bo's call was to replace him with Ross Els for the next four years. Water under the bridge; now we have Bray.
I think it's hard to deny that DL coaching was not very strong this year. I would've been OK with keeping Hughes and giving him another go of it, but obviously Riley has a better view of the situation and made the unexpected call after just one season. It's not easy to get both a good teacher & a good recruiter, and of course all eyes will be on the latter for the next guy.