If only the frame rate wasn't so awful.
Almost everything has been revamped: match types, Road to Wrestlemania, even the character select screens - which are actually small icons that are selected by a marker rather like that in fighting games. There are over 70 wrestlers in the game.
Create-A-Match mode has been introduced, and while the name is misleading - you can't really create matches - you can impose conditions and change the arena and such to make it a wee bit more interesting. This isn't really as welcome a feature as it seems though, because it just slows matches down.
WWE Universe replaces Career mode, and this is another 'welcome-unwelcome' feature because it changes Rivals of its own accord whether you like it or not and takes a lot of time. Exhibition matches are pointless because they get counted into WWE Universe mode unless you turn off the option for the game to do so.
Road to Wrestlemania mode has a Backstage feature where you roam around during matches. This is kind of slow, but you can talk to other wrestlers and there's some awful humour as well. You need to run around a lot more to unlock wrestlers than in the previous games.
In terms of movesets, the developers really did try. Now you can select what finisher to do on ladders and such. Create-A-Finisher mode lets you create finishers from the corner as well. This is quite a welcome feature.
Hell in a Cell matches have been revamped and this cell is more like the one in the WWE shows. You have to perform a finisher near the wall on the opponent to break out of the cell. Hell in a Cell matches are quite fun.
The game's biggest problem is the PSP version's awful frame rate, and given the excellent frame rate in the previous games on the PSP this can't be excused. Matches suffer from severe slowdown even if there are three wrestlers in the ring and Battle Royals and Armageddon Hell in a Cell matches are almost unplayable due to the severe slowdown. Interaction with wrestlers in the backstage of Road to Wrestlemania has the same grief. Voices in cutscenes are completely out of sync with animations.
If you have to have a WWE game for the PSP, you're better of with Smackdown! vs. Raw 2010 instead of this. It's fun when it plays smoothly, but the trouble is that most of the time it doesn't.