A couple suggestions for the leveling experience:
Player adjustable xp rates.
3x xp is great for people who want it, but imo cata leveling is already kind of too fast. Would be sweet to be able to adjust xp from a range of like 0.5x to 3x.
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Some sort of hardmode or leveling challenges.
Leveling is a joke in cata. Would be cool to have a mode that would increase the difficulty so its not mind numbing
Doesn't need to be complex, just something that increases mob hp and damage by a percentage for that character when activated would be enough.
I think these would be cool, because to me Cataclysm was always the expansion where the design shifted to where the game doesn't really "begin" until max level, and leveling became just a chore that you have to endure rather than an enjoyable experience itself. And, being optional, people who just want to get to max ASAP still can.
Player adjustable xp rates.
3x xp is great for people who want it, but imo cata leveling is already kind of too fast. Would be sweet to be able to adjust xp from a range of like 0.5x to 3x.
-----
Some sort of hardmode or leveling challenges.
Leveling is a joke in cata. Would be cool to have a mode that would increase the difficulty so its not mind numbing

Doesn't need to be complex, just something that increases mob hp and damage by a percentage for that character when activated would be enough.
I think these would be cool, because to me Cataclysm was always the expansion where the design shifted to where the game doesn't really "begin" until max level, and leveling became just a chore that you have to endure rather than an enjoyable experience itself. And, being optional, people who just want to get to max ASAP still can.