Brilliant! I think this is the most elegant way (that I've seen) of dealing with an issue that has infected a number of threads of lateCapping off levels at 10 and then giving feats instead of level ups or subclass features instead of level ups etc is the alternative if you want to play Joe the Fighter. Venturing into 11th and beyond means we're getting into some freaky deaky naughty word.
Keeping it Mundane (capping all classes at level 10 with feats etc, essentially converting e6 but e10); or
Going Mythic (accessing levels 11 onwards, and adding the mythic abilities to martials)
Would be nice if levers such as these and others were included within the DMG.