They'd call it the worst Pay2Win they've ever seen, leave a negative review and move on.

+1 and honestly they would be right about it. I have never seen any game go about the pay2win aspect in such an extreme way where it says 'you have to spend more' before you can get in the next league. No problem when it's done in a way where it almost can't be done because of the difference in power level. Reward restrictions should be separate from league restrictions.