I think Edge and Jericho should be last IMO.
Jericho has been the most consistant performer in the last 12 months and deserves it for that. But you also have to make them Main Event otherwise you de-value winning the Rumble and Edge's return. Plus HBK and Taker have headlined many times... its good to see two younger guys have the honour. Its been 7 years since one of HBK, Taker or HHH haven't been in the main event of Mania. I think i'm right in saying that Edge and Jericho have only headlined once before each and both lost.
I also think that HBK and Taker will be more than happy not being in the main event. They have enough pressure trying to live upto last years epic, which honestly is the big question of this years Mania. Can they do it again?