Sure, it'll be bad until rotation. Donk decks will ravage tournaments, causing overall disruption. SP will just become stronger than they already are, too. Evolution will be pretty much nonexistant. And yes, some people will quit. Not a lot, because...
There's the rotation.
Uxie's gone. Sableye's gone. The SP engine's gone.
And the game returns to normal, albeit significantly less fun for however long until the rotation.
OR...
P!P decides to do a mid-season rotation when the rules are changed. We never have to deal with SPs and ridiculous donk decks in a format where evolution decks are just too hindered to continue being near the top of the format. Nobody gets angry and quits because they play 2 turns in San Diego and never even get to draw a card beyond their first 7.
And the game continues along. Just think about it.
P!P, for the good of the game, please give us a mid-season rotation.