It'd be awesome, but needs some changes!

Dave Mustaine has some cool riffs, but his songs are extremely dull these days. His vocals are getting pretty poor, too. Writing with James could ensure the songs are better, as James is ace at over-writing song structures. He's got some cool riffs, but needs a kick in the ass by a better guitarist, I suppose. His vocals aren't that great either, but a studio project could be bearable.

Dave Ellefson is a solid bassist, I'm sure he'd be up for the job. Otherwise, Alice in Chain's Mike Inez would be a great pick!

Lars needs out, though. Replace him with a guy like Nick Menza (if he's not chasing UFO's or stalling solo releases) or Gene Holgan. Lars could supervise the writing process, but his drum skills are so incredibly poor, he can't even get One right!