By the way the fact that this camera (that none is expecting and none asked for) is coming out before both 70D and 7DII is a clear sign of how unimportant for Canon is the entire Gearhead/Pro-amateur/Semipro/Pro market.. T_T
Well, keep in mind that lower-end cameras sell a lot more than higher-end cameras and that if you intend to get people to move up to higher-end cameras, it's a lot easier to convince them if they already have one of your cameras (brand loyalty).
Canon saw that there clearly was a market for smaller cameras with interchangeable lenses (e.g. Four Thirds, Nikon 1, Fujifilm XPro-1, etc.) and obviously know that their large selections of lenses is one of the main reasons people choose Canon over other brands.
So with that in mind, they released the Canon 6D, their smallest full-frame DSLR to date and now this EOS-b (odd name..) looks like their smallest crop DSLR.
While many of us may want a 70D or 7DII, remember that Canon isn't there to only take care of OUR needs, no it is in the business of making money, they sensed a market (and I'd agree with them) and now they are addressing it.
I have no doubt that there is a market for a smaller DSLR, I mean many of us like the idea of a smaller camera to bring around everyday when we don't want to lung around the "big" camera with the "big" lenses. Now imagine the mainstream buyer
I am intrigued by the "ISO range is 100-25600" spec. If that is not an expanded range, it would probably be a new sensor. The 60D lists its 18MP sensor range to 6400 (12,800) expanded and uses a Digic 4. If the 25600 is expanded, then it could be the same sensor just with better noise reduction applied via Digic 5...
I'm guessing it's due to the Digic 5, which allows for better noise reduction thanks to its higher processing power.