The only way MS will have "won" this E3 is if Sony and Nintendo both decide to at the last minute not hold a conference.
Pretty much all we got from MS this year was third party non-exclusive games that will be available on PS4 (most likely with extra content and slighly superior graphics as well).
For exclusives we had....
Forza (good I guess for racing fans, but Forza 5 is not even a year old yet ....)
Halo Master Chief Collection (Repackaging 4 mostly ancient games together is hardly a killer next gen experience, Sony is guilty of this too with Last of Us)
Project Spark (cool I guess... remains to be seen if it catches on, and becomes an easy way for the non-initiated to start making games)
Dance Central (At least Kinect support is not completely dropped, but it would seem that the only thing that we have been able to see work on the Kinect since its launch has been dancing and exercise games ... kind of a waste of so much money and tech I would argue)
Sunset Overdrive (the highlight of the show, if MS gave us 2-3 more games that looked as fun and original as this they would have had a great E3)
Fable Legends (Fairly underwhelming. The villain control feature could be fun if implemented properly. Too early to tell if this will be decent)
Phantom Dust(I had an original Xbox and I never heard of this game ... was it supposed to be any good? Anyways, this is just another HD port of sorts from what we have been told).
Crackdown(I was quite surprised that this series is being revived after Crackdown 2 barely sold over a million copies. Too early to tell on this one, but if the previous games in the series are anything to go by I am not expecting a major hit here).
So when you boil it all down you have a collection of a few remakes, a small few titles that may be decent and only one genuine new exclusive with real potential to be a hit, Sunset Overdrive.
Not exactly a mindblowing E3, but this has been par for the course with MS. At least it was not as bad as their last couple of E3's ... although you could not make a worse E3 than MS 2013 if you tried.
I am not expecting much out of Nintendo or Sony, but at least a few interesting exclusive games would be great ... I don't need to see a parade of third party games that have all been announced months ago that will all be on every system anyways.
Above all else, Microsoft as well as Nintendo need exclusive games that are only available on their systems. If all they show is third party then people will just go for the systems with the best third party experience (PC and PS4 currently). Sony must still show exclusives as well in order to entice more gamers to justify the purchase of a new PS4 at a time when many games are still being made for PS3/360.
