Nono.. it should be allowed to avoid exp and still reap all the benefits of leveling up, all buildings/LTQ´s should be available for all levels and they should change the gamemechanics so a lvl 10 could be more powerful than a lvl 186 in a guildwar.

/<irony>

The only thing that gives a little too much exp atm is killing mobs in kando jungle/the barrens but other than that the levelingprogress is a bit on the slow side, i would personally like it even more if you got small amounts of exp from looting your own buildings and invading rivals to scout.