Generally speaking their strategy is mostly fine to continue from here. I see three main weaknesses they could improve:
1 - not enough family/everyone titles - and I don't mean Kinect. They need a much better library of titles for families and young kids that aren't Kinect mini-games.
2 - more exclusives vs timed or partial. The cat came out of the bag here and really apart from a few core titles few people see a 360 exclusive as remaining an exclusive. They need to either secure titles fully or pump them out more themselves
3 - improve Japan - to be honest this is probably their Achilles heel. Either Sony or Nintendo will outstrip them here, and if it's more lopsided next gen (for example Sony romping away with it) then this will make it harder for MS than any of the others to truly win WW. TBH I have no idea here because I don't think MS can change things in the region.
Given 3, unless MS really took a strong lead in US/EMEAA over both Sony and Nintendo I think Japan may keep them from number 1 WW so long as Sony/Nintendo do okay US/EMEAA.
Try to be reasonable... its easier than you think...
