On a main event level I could see
Dean Ambrose & Kevin Owens (The 2 superstars with the most attitude and actions that are unexpected)
John Cena & Roman Reigns (Would be the modern day version of the "Two Man Power Trip")
Brock Lesnar & Seth rollins (The 2 most exciting main event wrestlers)
But speaking realistically I could see...
Cesaro & Neville (Probably the 2 best ring workers, imagine the team move sets they could think of)
Mark Henry & R Truth (Both have been around for 15+ years, could definitely see some chemistry and funny moments if they paired)
The Miz & Dolph Ziggler (Could call themselves "The Show Offs" or "The A listers" they could make a great heel team)