Here is what I think;
The WWE is hoping for Austin and Rourke to sign on. Their ideal card would be Big Show vs Edge, Cena vs Austin, and Jericho vs Rourke. If Rourke doesn't sign on it will be Jericho vs Austin and the World title match will become a triple threat. If Austin and Rourke don't sign on it will be Big Show vs Edge and Cena vs Jericho.
They are keeping their options open at the moment.
As much as I'd love to see that final match, the fatal four way - I just don't see the logic in it. I can see Cena squirming his way back into the match (and I'm thinking a promo between Stephanie and Vickie - Vickie is bitching to Steph about Cena coming to SD etc, Steph after the RKO doesn't want anything to do with it, overpowers her and puts Cena into the ME at mania) but I just don't know how Jericho will get into the match.
^^^Replace Rourke with Hogan.
We can get Austin vs Jericho and Hogan vs Cena.. Or Austin vs Cena and Jericho vs Hogan.
Assuming that Cena doesn't get into the MITB match.
Isn't Austin too fragile at the moment, to wrestle? That's all I've been hearing - he's in too bad of a condition to wrestle again. Kind of like Hogan at SummerSlam against Orton. And don't even get me started on bringing Hogan to WM...
I honestly think Edge vs. Big Show will be a great match. Sure, Show's not fast, but you don't need speed if they can correctly use his other attributes, which they do for the most part. Edge has the speed to make up for it. Edge and Big Show together is pretty balanced. ANd anyone who thinks ANY match with Batista in it was good, you have no right to talk bad about Big Show.
I'm not a big Tista fan, really I'm not a fan at all. But I can say I'd prefer to see him in this match over Show. Batista, as unco as he may be, still has several advantages over Show. Show, they have to play that 'monster who can't be beat' card, use his size and 'strength' then have Edge work at him etc. It seems to be the same thing, everytime.
Batista, he can pull out the power card, but he also can use his speed as well, he's not as slow of un-agile (that even a word?) as Show. He can get around the ring a lot easier, he can do a fair bit more than Show. I can see the offence being more exciting both ways (ie offence from both Tista and Edge being more varied) than Edge getting in some cool offence to take down Show (ie having to come off the top rope to take him down etc).
With that being said, it's not going to be impossible for Show and Edge to have a good match. It's just going to be that 'typical Big Show' match.