It looks like we'll be getting mutations. Maybe not many on release but some at a later time. Looks don't always play a part in mutations as we know and Andrea seems to be focused more on the visible mutations. He wants them to look good, which is awesome and shows he's pretty concerned about the quality of the game. The non-visible mutations I think will be easier to implement, simply because It's more about chemical reactions happening inside the norn which no custom visible queues.
So this norn has a mutated gene, this gene misfires when the norn eats food. Say....something like starch is converted to alcohol. You will end up with a very drunk norn who stumbles around the world most of the time. However these animations should already be in the game if norns are getting drunk from drinking hooch (or something similar).
I'm assuming these mutations might already be a given and the more far-fetched mutations are what Andrea is concerned about. The physical ones. I would be blown away if there were a good amount of physical mutations apart from pigment. A limping norn? Sounds awesome to me. Maybe even more extreme things will make an appearance later on. It's so exciting!
I really hope we can get lots and lots of wonderful mutations! :)