I mean, that IS what they're doing, though. They've slowed down on the amount of Champions they're releasing in order to dedicate more people and time to the rework teams. In case you haven't noticed, they're focusing a lot on game balance this year, as well as reworks. They're close to fixing the only-adc-and-support-in-bot issue (they need a bit more tweaks to make marksmen and supports still viable there together while keeping them not the strongest), and most junglers are relevant rn. They've also been looking at fixing complaints that a lot of people have this year (age-old complaints about mage items, etc).
Not to mention, as BornToBeAhriGod had said, the balance and Champion design teams are different and not linked together by anything besides communication between them-- otherwise, they don't work together at all.
Also, I don't see what's wrong with Galio and Urgot. Urgot and Galio are a bit unplayed, yeah, but I'm pretty sure the reason behind Galio is mostly just meta shifts. Tanks are out of season rn.