What incentive does Mark Rein have to do "damage control"? Here's a hint- Epic makes games for every platform (except maybe Wii U LOL). Why on Earth would he be trying to defend Microsoft? Just because Gears is a Microsoft property doesn't mean Rein has anything to gain by saying this. As a prospective buyer, Rein speaking here unabashedly tells me that the big third-parties are very happy with Microsoft and that's a crucial piece of information.
However, if tin-foil hat conspiracies keep you going, by all means continue.
While I see what you are trying to point out, I don't think your examples are great, while Epic make a middleware multi-platform engine they themselves haven't really done much on the console platform this generation; sure they might have put out UT3 on both 360 and PS3 and even given the PS3 version an extra helping with its bonus features, but besides that Gears has really become their meat and potatoes next to what they can get out on mobile platforms.
Gears of War is one of MS biggest 360 exclusives next to Halo, Fable and Forza, and iirc Forza and Fable are usually a few million behind Gears, so I think he obviously isn't going to go round and bad mouth MS when they work so closely together. Sony being in general gaming news for being good to work with now really comes from them being a bit shitty with their hardware and developer relations going into the current generation, we aren't going to hear that from developers at this point because they don't have a system to talk about and this sort of work has already been going on.
Being the VP of a company that provides one of the most popular console engines around I don't really expect him to bash prospective buyers and hardware manufactures anyway; but evidently Nintendo and their hardware is starting to become the butt of a lot of jokes, and I imagine it is somewhat frustrating to Epic too as their latest engine and where they expect to make money licensing it off isn't going to happen on the platform because it isn't worth the time or money.
With all these shitty rumors making the nextbox look bad while the MS guys and devs just brushing it off. I really think they will blow us away at the reveal.
We will have to wait and see, if the rumours end up being true they might not blow us away on the graphical, more powerful hardware front, but that isn't everything these days and MS is a big company with lots of things going on, their main focus has and will no doubt always be software; I expect some pretty snazzy features from them.
