Naturally, critical imbument increase the exp/h the most in most cases.
However, it is difficult to estimate the exp/h growth, mainly because it depends on the character gear, skills and the monster's HP and the respawn rate.
Specifically, if the critical hit makes you finish pulls faster, and the respawn rate is good enough, you should definitely see increase in the exp/h.
On the other hand, if you deal with monsters with little HP and you don't save "attack cycles", or you overhunt the spawn, you probably won't notice improvement in the exp/h.