If it pushes past 10, then it should probably cap at 12 or 14. Purely speaking in terms of single class, level 12 gives you your third ASI (more for fighters and rogues), 3rd attack for fighters and 3rd die for cantrip damage. 14th level gives most classes an additional defining ability for their class. Rangers get screwed because their 14th level ability, vanish, was given to everyone for free when they gave cunning action to everyone. Kind of funny that the worst designed class in 5e got screwed over by the dev implementation of hide, and it also shows you just how powerful hide as a bonus action is in 5e.. its a 14th level core ranger ability.
