I think if you learn more about the OCU program you will find it has a long and excellent track record and is considered one of the best in its field. IU is also a very strong MT program. D has friends there who love it. Either would be an excellent choice. But the 2 programs are very different. So it depends on what the OP is looking for. I think I compared the 2 schools’ pros and cons pretty well in post #1 and pointed out each school’s strengths and weaknesses.
One point regarding post #5, there is a big difference in how the 2 programs operate in relation to their celebrated Schools of Music. OCUs program is a music degree in the Bass School of Music. All MTs audition for all operas as well as for all musicals. VPs and MTs share voice teachers and studios. They take the same piano, theory, aural skills, music history and other classes together. At IU, the MT and music programs are separate. The MT program is not part of the prestigious Jacobs school. As post #6 indicates, I would not go to IU with the expectation of getting to study in the Jacobs school.
As far as selectivity, I think both are highly selective with their audition process. OCU has a slightly larger class but I am fairly certain they audition a larger number of applicants. OCU also offers spots in VP and Acting to some talented students for whom there is not a spot in the MT class. This is not the case with IU, so it may make it seem like OCU extends more offers. It may. Just not all in MT.
Just as an FYI: The Acting and VP programs at OCU are also great programs with lots of successful grads in musical theater (i.e. Alex Enterline recently was the lead in the National Tour of “Nice Work If You Can Get It” and Katie Postotnik was recently the lead in the National Tour of “Ghost” - and both were BFA Acting majors at OCU). So if you are one who is offered a spot in one of those tracks, I would look into it further.
All that to say, I think both IU and OCU have great things to offer. But they are very different. It is just finding what is the right fit for you.