Honestly? If they implemented this suggestion, I would probably stop playing. I did not buy this game to be shoe-horned into playing my character exactly like everyone else in order to be considered "efficient" enough to garner a party invite. If I wanted that, I'd go back to FFXI. I bought the game in great part because it presented the opportunity to mix and match abilities to create a vast array of tactical combinations, something the FFXI subjob system was supposed to do but only did in a very limited fashion.

I keep hearing people complain about class uniqueness... the lack of uniqueness doesn't stem from the way the classes are implemented, it stems from the fact that the game doesn't really challenge you to do more than spam buttons. Change classes to be more restrictive in scope and less entertaining to play, and you still won't have the coveted party dynamics everyone's apparently looking for, you'll just have a lot less players on your server to form a party with.