Hangul covers Korean language, IPA covers all languages. For example, some languages use clicks; though to be fair, IPA only currently covers 5 of the 6 clicks. Again, point is not IPA is the solution, but that having a common notation would make learning languages much easier and learning only one written notation would be needed.
I just wanted to use a concrete example of a featural writing system. It would of course not be Hangul if it had to accommodate all phonemes. The other direction to take would be to create a sophisticated (probably ML) model that could enable certain features to be optimized, like speed of syllable recognition. If we are constructing a modern writing system then that would definitely be a good approach.