I'd say have the Triple Threat, but make it an elimination match instead of the traditional first fall. This will allow Punk and Cena to carry 25 minutes of the match, Punk gets eliminated, then Cena gets his WM moment after a 7 minute one-on-one with The Rock. Allows Cena to finally pin The Rock, and makes the match a lot better.
And allows Taker to take the year off, if needed.