First off, that it should be the final season, since NBC is losing the evolutionary arms race and changes of television, but that they also use this as an opportunity to make the show go with a bang than a whimper, like diverting money from pilots that won't last two episodes to fund like, 30 episodes of SNL, each given more time to be funny.
Now the hosts:
-Neil deGrase Tyson
-Barack Obama (sitting president hosting)
-Gilbert Sheldon (underground cartoonist, to see what'd happen)
-Anyone from a Mystery Science Theater 3000 movie
Final episode: A giant reunion of SNL alumni still alive (minus Chevy Chase, due to his homophobia, and borderline alcoholism, which reminds me of an incident where I was touring the Community set at Paramount on Melrose, I saw Chevy Chase and said something like 'oh my god, you're Chevy Chase!", because that was pretty exciting to see a legend in any case, and he had a half-empty bottle of wine and just was startled, like he was about to have a heart attack.) doing classic sketches and a bunch of new ones, before a final goodnight form the cast. And then hives of killer bees are released into the studio as the credits roll. What, you wanted it to be a sappy ending with no gag or anything?
Reader suggestions are most welcome, since I know there's a ton of stuff that could be done, for example I could only think of one female host, so please, comment away.