The only game, on console, of any significance is call of duty and I really can't see MS making it an x box exclusive given the amount of coin it brings in.
Yeah they'll stop the early access stuff for PlayStation players but other than that I don't really see anything to be worried about.
Sony have snapped up insomniac, they've got santa Monica, guerilla and naughty dog plus polyphony. Really wish they could have kept hold of quantic dream but they'll be releasing multi plat games too.
It's all about the quality, which I think is something MS really lack at the moment and buying Activision won't change that, it's just a guaranteed banker each year With CoD sales and WoW subs.