There is a lot of work to but I think the multiplayer should have been its own game. love kratos but we know his story. They should focus on tithe world around the god of war games and give other, "lesser" gods some more shine. If the multiplayer was its own game then you can do that and have so many different levels, abilities and fighting styles.
I've a post talking about something like this, but more like a coop campaign without kratos. The main character as our warrior and obviusly a multiplayer mode.
If you read it just ignore all that discussion lol.
The bigger issue is what resources the multiplayer takes away from the full game itself. Multiplayer gets all the focus so you have to wonder how dialed in and unoriginal the single player will be.
I don't even like the control setup for multiplayer and we're going to be stuck with the same setup for single player most likely. I don't like the block/parry routine or L3 being run.
A game totally dedicated to MP and I think it would be pretty awesome, especially if this MP is good. It'd be able to expand huge in all areas and that'd be hella cool.
I love the god of war universe, they have such an awesome and action packed spin on everything it's cool.