Did you use absolutely all of them?
For example, Reha has 6 battles that must be done with AK on: Harrus, Marakash, Sarkash (in the Cave), Ziraks and Harrum (the 2 arena fights), K'Tahu.
Nameless has the following: Restless Zombie, Vlad Vegeto, White Night and Dark Mistikus. 4 more.
Elon has a ton: Uldara, Moro, Uchkuk, Shenobi, Zilgadis. In addition to those, you can find Tomas Torkve, Morto and Weed there. That's 8.
Well, maybe those may push you towards lvl 59, and maybe a bit more, but it is a matter of a little luck as well, I guess. Besides, to get to 60, even with all +XP stuff, you need to do quite a lot of suppressions of rebeling items for like 40-50k extra XP.
In any case, it's up to you to try it out. Your result is great as it is
