If you think ESPN is going to ruffle the feathers of the power conferences, for BYU (or anyone else), you are wrong.
It does not matter that ESPN owns the television rights of the bowls. The Power conferences do not need ESPN, ESPN needs them. As is evidenced by the bidding wars that happen every time a BCS conference television comes available.
With Comcast, Fox and others looking to get more and more collegiate coverage, ESPN is not going to alienate their biggest clients to make way for BYU. Since BYU is not eligible for the Non-AQ bid, if they get an at large it will most likely come at the expense of a power conference team. If ESPN pushes a BYU over a Big 10 team, they risk alienating their biggest money makers. ESPN execs are not that dumb.
The bowls will choose who they want, and ESPN won't have a say or any influence. If you think ESPN will, you don't know a lot about the bowl selection process and the power the bowls and power conferences hold.