I think this is a great thing for several reasons:

1) Encourages people to log out which means less server strain.
2) Encourages people to spend time in housing crafting which means less lag running through Ul'dah.
3) Encourages people to breathe fresh air or play FFXIII-2! .. haha

I don't see a problem with it. People leveling too fast isn't a problem, it means more people to do endgame with - even if they have to learn it fresh. Most people don't learn how to actually play their jobs in exp parties anyway. Every time someone pulls hate off the tank, they're doing their job wrong or the tank is doing their job wrong. This gets fixed in endgame where people learn their limits and roles.

Much like in FFXI, exp parties were meant to get you to endgame. Black Mage in XI exp was all about magic bursting Freeze on a Distortion skill chain or teaming up with other Black Mages and timed-nuking something. Endgame Black Mage focused more on crowd control and then casting a nuke or two when they knew it was safe enough to do so without eating dirt.

Maybe my friend will be able to catch up to me now since he plays so infrequently!