He said there would be an exclusive title from EA. I don't think this is it. Rumors have been pointing only to Respawn's Titan. If Mirror's Edge 2 is really being revealed at E3, it should be multiplatform.
Could be, but not the sort of exclusive MS is looking for really. I mean, it's a fan favourite, but not a significant system shifter by any means. It would be a Bayonetta 2 in exclusive terms, I reckon.
That's a classical thing when retailers don't have an official RRP. With the "preorder and we guarantee you'll pay the lowest price until release", if they put too low a price on a preorder, they're doomed.