I love Stone Cold, but as a GM? I dont know... Its always great to see him come back and rebel against authority. Not come back and BE the authority. It may make things a little bit crazy for a while, but it would start to get annoying after a while, with things going all crazy all the time, and there being no rhyme or reason to anything thats going on. They need someone who is able to step in and make it look like they are capable of keeping everything in line.
I think as far as Stone Cold is concerned, it would be best to have him a role much like Hogans. Make so many appearances a year, with the option for more if some sort of angle opens up and calls for it. I still freak out when I hear the glass shatter, but if it was every week, I think some of it would wear off, until he got to be the new Ric Flair. The one that just never goes away.
By the way, I still think the #1 pick would be Eric Bischoff.