These focal lengths would make a lot of sense in a EF-S lens. (Although, it is questionable if a 150-300 f2.8 lens would be noticeably smaller than an EF lens?) Canon makes the 17-55 as an F2.8, but apart from this, they are lacking in fast EF-S lenses. Personally, I'd much rather see an EF-S 15mm f1.8 L. Especially if it is small, pocketable and takes regular filters. Other manufacturers seem to cater well for APS-C sensored cameras. With Canon, you sometimes get the impression that if you're not using a full frame camera, you are a second class citizen.
It does seem like that, which is curious given that they only really have one full-frame camera, and technologically speaking, their half-frame (or APS-C, or super35 sized) 7D, or their a-little-more-than-half-frame 1DmkIV are their most advanced cameras. Also, the vast majority of their sales are half-frame cams.