He'd be perfect for his wisdom, knowledge, and experience. It's probably not the best idea, though. One reason is that two guys in their 70s as Pres/VP might not be the best way to prepare for the future.
Another reason is the US Senate. I used to think that there were ten or twelve decent US Senators who would be on our side when things turn around. Now, the only one I'm really sure about is Sessions. There are some younger Senators with potential, but there are more who've infested the place for years who need to be kept under control. I can't imagine how that's done unless Jeff Sessions stays in the US Senate.
That’s a good point about needing him in the Senate. However, I don’t know if you support Newt or not, but Newt is 74 whereas Sessions is 69, so Sessions would be younger than Newt.