I'm not sure how much weight Nebraska has in the Big 10, but you can guarantee they'll be fighting tooth and nail to keep Texas out. Texas is the reason why they left to begin with. It'd be interesting to see how Texas reacts to actually having to play nice for once, though. I doubt Ohio State and Michigan would put up with their shenanigans for long.

As for the OP, I just don't see Oklahoma as a good fit for the Big 10. As awkward of a fit as Rutgers is, it makes more sense than Oklahoma does. Academics at Oklahoma have never really been up to the Big 10's level, and the culture down there's more Southern/Southwestern than Midwestern. Kansas would at least make sense. I'm sure the conference itself would love Oklahoma, but the presidents outside of Lincoln would have a different view.