One of the main reasons high-achieving students who have access to an IB Diploma program choose NOT to pursue it is that it includes many requirements and can make specialization challenging to impossible. The IBD is a degree – you end up with two diplomas, one from your high school, the other from the IB – and as such, the holder must have a certain level of proficiency in a broad range of subjects (as well as higher level in a few).
Students who want more science or who hate FL, for example, may find other rigorous, but less "balanced and comprehensive " paths much more appealing. Nbl
I admit, I love the IB program because it really encourages critical and interdisciplinary thinking, and it is regularly updated by educators around the world to ensure its relevance. With that said, it really isn’t for everyone.
I would map out a 4 year schedule for each option and see if anything leaps out suggesting one path over the other.