Leveling a mage..ya
 

I get xp quicker soloing on my monk at lvl 35 then i do soloing on my lvl 11 mage. Something is wrong with that picture. Discuss...

duo instead.

Exp will pick up when you start to chain.

A solo mage is only as strong as your pet. At level 11 you're still using the level 8 pet, thus will be slow. Level 12 will fly by with the better pet then start to slow down as you approach level 15...and this pattern continues till 49. (post 50 pets just stop scaling well)

At level 48 you feel gimped, at level 49 you feel like a god, then it slowly goes down from there.

^ This. With the level 12 fire pet you will be soloing yellow cons. Also if your pet is eating up exp then nuke harder. :)

Also, try and give your pet rusty 2-hand weapons. My level 8 pet was hitting for like 20 damage with a rusty halberd. Sure it takes 50% exp doing damage like that but who cares if your killing 10x faster.

Also (not sure if this applies to you though) melee do profit much more from being twinked than casters. It makes a world of difference to them where it only increases the number of targets a caster can take down before meditating.