I don't particularly care myself whether an RPG is class-based or not--all I really ask is that levelling up makes substantive improvements to your character's ability, e.g. don't just add 2% to damage or something like that (back when I played WoW it was an egregious offender in this regard, although I guess it may have improved since). This is why I don't like level scaling as a general rule, because what's the point of my character becoming more powerful when everything else does as well? I ought to be able to take my newfound power and absolutely rip through some enemy that was annoying me a couple of levels ago!