I there are several nice options here (minus Ric Flair and Velvet freakin' Skye). Regal was great the first time around, and has always been one of my personal favorites. Very funny, and can draw serious heat. Has the pedigree of a prick boss too. JBL is another guy, who much like Regal, can stay relevant while not wrestling. His mic skills and character are strong enough to draw real heat while not being in the ring. Both guys, for my money, are great options.
But the guy I would really like to see get the job is Bret Hart. Is he as good on the mic as Regal or JBL? No. But Bret is my 2nd favorite wrestler of all time, and I would like to see him week in and week out if I can. He has become more comfortable talking in front of a crowd. While he was never Duane Johnson on the mic, he was always better than given credit for. During his heel run with the Hart Foundation in 97, he was top notch on the mic. That guy was creative, and could draw a lot of heat.
My hope is Bret Hart will take on this role. He is one of the most respected guys in the history of professional wrestling, and I think he could not only be entertaining, but he could add some real credibility to the role of GM. With all of this guest host shit, credibility among GM's is needed right now.