I would take W-St if they played again. This line opened at 3.5 and I, like you, bought it to +4 at -120 (at the time).
The line closed at +1.5 at a few books so the early placement paid off.
The most important thing for these two in the tournament will be who they get matched against. Creighton was no match for a much quicker St Mary's team so if they face a team like Michigan or Miami, they will be in trouble.
Wichita could give some of the Big East teams or a team like Duke or Michigan State a very good game. I think high peforming offensive teams would win comfortably against them.
Continued good luck to you.