It's a pretty interesting situation, one worth watching.
However, objectively speaking, I think the number of core games that will emerge from Microsoft's list of developers will still be quite a bit smaller than what we see from Sony's Worldwide Studios.
Many of Microsoft's new developers seem to be focused on the Kinect experience or media hub functionality. Don't get me wrong, I think it's a good thing that Microsoft is ensuring that Kinect 2.0 will have good games rather than depending on third-parties for that, but I'm not convinced that many of those titles will resonate with the audience we have here.
Also, as has already been pointed out, several of the Sony studios work on more than one project at once. That makes this list a tad bit misleading in terms of total projects.
And, as the article states, Sony (and Nintendo) get Japanese games that have little chance of landing on the next Xbox, such as franchises from Atlus or Compile Heart.
Still, I think Microsoft will throw out some new core IPs next gen, and I imagine they'll be high quality. If they revamp Live to something I feel is acceptable, then they might be able to capture my attention.
