Of course, even if this very day we said NO SOUP FOR YOU and locked Abyssea to 75+ characters...people would STILL be leveling faster than they did in the bad old days. You could sit there on your I-don't-want-you-in-my-exp-PT-forever-alone job of choice from that era now and be guaranteed a steady rate of exp gain.
I don't care what job you are. Given baseline equipment, you can kill EP mobs. If you can kill it and it gives exp, all it takes is a GoV/FoV page and you're looking at advancement at a pace that isn't grindingly agonizing. For anyone.
That's good. It's the overwhelming mass exp generation that is Abyssea that's broken, where players literally don't have to move for 69 levels straight from one place, in perfect safety while the guy with the great axe and his healer lulz their way through for you. Heck, I wouldn't be surprised if you couldn't just bot the healer and auto-level 17 people with one guy twoboxing his computer (yes, botting illegal. Someone should tell all the fishers I keep seeing that.). No threats. No worries. Just dingdingdingding hey I'm 99 now, YAY I R TEH SPECIALZ!
Abyssea's exp system wasn't a "fix" for grinding. It was the death of the exp system, period, reducing the process to something of a zero-risk proposition for 16 people at once. GoV/FoV was the fix.
Abyssea was like having the human race become immortal and invulnerable, followed by GoV/FoV's discovery of the cure for cancer.