I haven't been to every stadium in the conference but
KU's will take some major work to be better than Trice in my opinion. I was shocked when I went there in 2005.
Oklahoma at one time had gravel for a walk way around the stadium. The inside was a bowl, but it had little character.
I've been to OU's stadium several times, once before the somewhat recent work where they added the second deck to one side... that place is simply amazing and it's spot in the direct center of campus I think is very cool. IMO the best college stadium I have ever been to and the best stadium I have been to other than Reliant.
I do agree that the practice facility is still top notch. But Jack Trice is probably one of the worst in the Big 12 comparatively, although I do say that without having visited several of the stadiums.