Here's my take one what to do with some of the current WWE roster who seem to be... not doing anything:
Tyson Kidd & Evan Bourne
Pair up Evan Bourne & Tyson Kidd as a heel tag team when Evan returns, managed by Paul Heyman. Have them start a rivalry with Sin Cara and Rey Mysterio Jr which ultimately has the two teams facing each other for the tag titles at WM.
To the point, here is my suggestion for the main event at WM:
Rock and Cena versus CM Punk and Stone Cold
Punk and Stone Cold win, but Undertaker shows up. He knocks out CM Punk post match and celebrates with Stone Cold -- and all the legends applaud The Undertaker's official retirement
How Cena and Rock team up: Cena helps Rock after getting jumped by Punk at an earlier