The only sport upside for Kansas is men's basketball. Football is awful. Most sports outside of men's basketball are awful as well. A blue blood men's basketball program is the only upside. Small population. No new recruiting territory. AAU membership and being located in a border state are the pros outside of sports.
Oklahoma would be a slam dunk addition. National football power. Some success in certain Olympic sports. Would need the addition of Kansas to not be on its own island outside of the contiguous footprint. Small population and no new recruiting territory, but a national football team similar to Nebraska. No AAU membership, but I believe OU is a school that would be worth adding that is not AAU.
They both have pros and cons, but I think OU has more pros than KU.