Heres my predictions on a match by match basis.
John Cena vs. Umaga: Last Man Standing for the WWE Championship:
I don't really think that Umaga is going to get the win here. Cena pinned him clean at New Years Revolution, which sudjests to me that WWE does not see the need to protect Umaga in this fued. I think Cena will get the clean pin here, since if Umaga wins, then more the likely, he will have to main event Mania 23, or lose the title extremely quickly.
WINNER: JOHN CENA
Batista vs. Mr. Kennedy for the World Heavyweight Championship:
Batista vs. Undertaker seems like a very probable 'Mania main event, so I can't see the title changing hands here. Mr. Kennedy has been booked strong though, so I think that there will be some sort of disputed finish here, but with Batista getting the win.
WINNER: BATISTA
Bobby Lashley vs. Test for ECW World Heavyweight Championship:
I really don't think that Test will get the win here since I don't think he is really strong enough to draw on top right know. I see Bobby Lashley getting the win after Hardcore Holly costs Test the match and the title. Which then sets up a fued between between those two, and allows either R.V.D. or CM Punk to move into a title feud.
WINNER: BOBBY LASHLEY
M.N.M. vs. The Hardy Boyz
I think the Hardyz get he clean pin in this one in what should be a good match.
WINNER: THE HARDY BOYZ
The Royal Rumble Match
I think that we will get a Shawn Micheals, Edge, Randy Ortan final 3, with Edge and Ortan costing each other the match, and Shawn Micheals winning the Rumble. I think that we'll then get a Cena vs. Micheals vs. Edge, vs. Ortan at 'Mania 23.
WINNER: SHAWN MICHEALS