I don't think Buchanan would do a very good job with it, to be honest. I assume that the show will stumble forward in some form for the next three months, then go off the air for good after the election.
As Santander noted, Pat Buchanan is great but not as a host. I'd recommend someone like Brian Lamb if I had a voice.
I just don't see why it's obvious that the show is going to continue at all, to be honest. Like I said, they may very well keep it going until the election, but why continue McLaughlin's show indefinitely after he's dead? The panelists are mostly pretty old themselves, and I don't think it's any kind of ratings powerhouse.