The truth is that I'm not sure, I would have to see the third form of each monster and compare. At the moment I am very happy with the results that krog gives me in his third form. Mudgill has surprised me a lot by what I say above. But I would have to see. Woad if you have haunted synergy spawns an absurd amount of food, and chikia is always good. But as I say, I would have to compare a lot more the 3rd form of all the monsters that I am missing :) most likely they are all balanced.
Both Mudgill and Krog, if you have them in their third form, I highly recommend you the item that makes the ability cast twice.