The experience is far too low. It is a great but very difficult quest, and getting only 4 exp per ogre is a tad low, it's lower than any H'bala spawn gives on a quest even.
On the other hand, Sinister's enclave reward ratio could be toned down given the risks involved. It's more of an endurance test for a balanced team, while Mist ogres is always a very challenging and dangerous experience even for the most competent party.
I've had the chance to run these quests quite a few time, and I'd be in favor of increasing gains of Mist ogres, and decreasing gains of Sinister enclave to reflect their respective risk/reward ratio more appropriately.