It opens up the possibility of high performance low scaling class though.
For example Barbarian.
In exchange for having rather terrible scaling, their skills come with really high skill damage for the level you get them, so during that period you have much easier time leveling than others (and then people complained about it…remember all the “BARB OP NERF PLZ” threads in icbt2?)
So if what you want is to simply level fast/easily, picking/dropping these classes will be better than building based on lv cap.