If you're talking about cutting out Fukuoka, I'd say that's an interesting plan that opens up the possibility of exploring Kansai in some depth. (Kobe, Osaka, Kyoto, Nara, etc.). You could use Kyoto as the base for the entire time - I don't see a reason to decamp to Osaka. (But if you want a change of hotel, then why not).

If you're talking about cutting short Fukuoka, but not cutting it out entirely, then I think your original plan is probably fine in terms of balance. You could lump the Kansai stays (Osaka and Kyoto) together if you wanted to.