I totally agree with Jericho. just go look at the previous 6 wrestlemania's and have a look at the horrible lack of variety in the Title matches. In the last 6 Mania's there is 28 world title match spots and here's the breakdown:
HHH - 5
Cena - 5
Orton - 3
Edge - 2
HBK - 2
Undertaker - 2
Batista - 2 (Injured for two of the 6 manias)
Angle - 2
Big show - 1
JBL - 1
Eddie - 1
Rey - 1
Benoit - 1
Obviously Cena & HHH dominate but the other names on the list are guys that. I mean two of the guys on that list are dead, one is retired and one is with the rival company. So that leaves 9 guys on the current roster including Rey & Big Show who i couldn't imagine as champion again in the near future. So you're left with 7 (HHH, Cena, Taker, Batista, Edge, HBK & Orton) now you can probally add CM Punk & Jericho to that list but where is the future?
I mean would anyone bet against both title matches at the next Mania coming from that pool of 7 guys (HHH, Cena, Taker, Batista, Edge, HBK & Orton). Coz i wouldn't.