Mr. J. Nelson and I had a small, albeit to the point conversation about this earlier. It follows a lot of what has been said already here.
While Sajak is my first choice *dun dun Dun DUNNNNnn... thomp*, yeah, I'm about 99% sure he wouldn't want that daily commitment anymore, especially on top of other things he does. While his lifelong ambition of doing a talk show might pull his heart strings for doing this, there's the fact that he will probably sign only one more contract renewal for Wheel before saying goodbye (he's stated he has between 2 and 10 years left of hosting it), which would open up more time for him for doing this at a later point, while working him to a grind in the interim. Committed to hosting Live into his 70's would definitely be a strong longer-term commitment, I think, in this case though, and would still be appealing for the show's producers. I'm pretty sure Sony wouldn't say one word about doing both either, except if Sajak was talking about leaving Wheel in particular in order to do Live.
Also being a fellow Marylander, I can tell you that it takes about 4 hours to drive from Maryland to NYC, but that can be cut down by about an hour taking Amtrak. That would mean he'd have to be waking up very early to get to NYC on time. I'd think the show would either have to move to a later time period on the East Coast (10am maybe?) or... well... not be so "live" anymore. Neither idea is particularly great in my mind, so that could be a potential issue too.
My preferences, otherwise, go towards the likes of Jeff Probst, Ryan Seacrest, or possibly Anderson Cooper (forgot he had his talkie coming). It wouldn't rub me wrong either if they did rotating hosts every week for the forseeable future while Kelly is the "pillar of strength"... or something, for the show.
/Yeah, I'd have a pillar of strength to give her.