Unless you made up your own definition, CM Punk having the belt for over a year is not a transitional run. He beat Del Rio to get it, defended it against Cena 3 times, Ryback 3 times, Chris Jericho 2 times, Daniel Bryan 3 times, Kane, Dolph Ziggler, The Miz , The Rock, and everyone else who was a top superstar throughout that run except I think Randy Orton.
You cant call that a transitional run just because "it didn't feel important to you" or because of Cena's shadow. Cena's been doing that to everyone for years now. That'd mean everyone except Cena is a transitional champion which is silly when the belt is on one person's waist for 13+ months.