One player rolling really good stats is the same thing as a player rolling really bad.
If the dice gods make one character superior, it automatically makes everyone else inferior.
Ability scores are actually the only place I feel everyone needs to start on a level playing field, because everything else is the player's choice. I like systems that allow for a lot of customization and optimization, balance is a trap. For your build to matter, it has to have the potential to improve or degrade your ability. But dice rolls are random. There will if he no randomness in the strength of a build.