Yep, the diseases have a chance to be absorbed. I haven’t noticed poisons being absorbed, though. Probably because there’s no magicka being used there’s none being gained, and half of the time they work. I’m pretty sure that Shouts have a chance as well, since when Jerric was not skating across the floor on his back in the last ruin he was gaining magicka. Of course there were also draugr covering him in frost the whole time, so I can’t be sure that Shouts give magicka either.
Also you have to be careful with mods since people use spell effects for things that are not magical, like snow sticking to you.
Taking magicka regen down to zero is really necessary for the Atronach, in my opinion.
eta: Oh, and there's also a Restoration spell you can't use because it refills your magicka.

Circle of something. I mean you
can use it, but it's kind of a cheat so I don't. Although that may be fixed in the unofficial patch. Jerric hasn't gotten that far in Restoration yet.
This post has been edited by Grits: Dec 1 2013, 09:02 PM