Jonin medal boost to power is negligible. The only thing that continuously secures a player stomping other people is they money they spend. The medal itself has good perks but its far from "OP". It honestly levels the playing field for the most part if anything. On my server there are a few 100% f2p players who can stomp medal users. Money isn't everything. If you spend your coupons right and grind for it there isn't anything that would stop you from being just as good. Realistically, the top people on your server will continuously drop money and you wont be able to compete with them anyways. And who knows they may up and quit. But I wouldn't ever quit a game because of a slight disadvantage.