The exp they give in toi could be increased, especially at high levels like toi 70-100. You only go up to do the boses and it could be a decent leveling area, not as much as Talkin Island or Dragon Land but like Giran.

It's boring to hunt in places where they only give exp. Or look for items where they don't give exp. Toi's upper floors should give a little more exp due to their difficulty

Techinally they do due to the monsters being higher level. 
Exp zones don't really give good drops vs toi which does and is really good for adena making. 

There is lots of new stuff coming with the new client. 

So no reason to edit exp on locations at the current time. IMHO

Also leveling is really easy due to exp zones so its good to have non exp zones that can be used for boss hunts  / farming