Honestly, I would rather see racial modifiers adjust the caps. Something like 18 for humans across the board, but that dwarf can have a CON 20 and the elf a DEX 20. Their maximum abilities are simply beyond what humans can do. Now, to me, that makes them "alien" in a way so they aren't just humans in make-up, etc. We've been doing this for a while and I like it. We added a feat, Raising the Bar which allows you to increase the max for one ability score from 18 to 20, so a human could be a strong as a dragonborn (for example), both with STR 20, but the human has to invest in it.
It could probably be reworked to be more popular, but as I said I like it and think it has merit. I'm tired of seeing 18's at level 1 (which is why I stopped rolling for scores, too.) because that little edge makes the PCs too good for me. shrug