Valid criticism, although I would still vote to put IPA in language classes in the absence of something more useful. A linguist using their own tools for field work is fine, but trying to learn languages with average folks is very difficult because they don't know how to talk about sound. It's a very basic problem and I think it would make international dialogue a lot better. The aesthetics of pronunciation have a powerful effect when trying to meet foreigners and right now there is a very limited awareness of phonology among average World Citizens. Perhaps I'm just voting for phonological education, but I've found IPA able to solve quite a few problems and I think its dissemination would have a similar effect on others. If it or any other system needs modification, I would simply propose that there be a process for evolving the system as problems emerge in the collective consciousness of the system.