The trend in high end mirrorless cameras is that they are getting larger not smaller. The NX1, which I've used, isn't any smaller or lighter than a DSLR. I'd expect the A9 when it arrives to be similar. Although the small chassis MLC's generate a lot of "gee how'd they do that" buzz, the "lens with a camera attached" ergo's are off-putting for a lot of serious shooters. You may not agree, but that's what many think.
edit .. Interestingly, the only bundle that's available for the NX1 includes a battery grip. Doesn't sound to me like smaller and lighter is what they are going for.
Indeed! The small factor is fine for a street photographer's tool, which is why most mirroress cameras went with rangefinder style designs. Not an issue with a 25-50mm prime. But, when you start slapping on large glass the small factor advantage erodes an actually becomes a detriment. So, one of the commonly touted advantages of a MILC (small size and light weight) either becomes a detriment or you make your MILC the same size as a DSLR to improve large telephoto handling. Although you still have the other principal MILC advantage of seeing the exposure changes you make reflected in the EVF, the disadvantages of lag (especially under low light), lower quality view and higher battery consumption. MILC's are interesting cameras---but it's a huge mistake to assume they've rendered the classic DSLR obsolete. This is especially true for action/wildlife/sports shooting!!!
I think Canon does deserve some blame. Personally, I have grown to hate the stratification of their cameras, missing features and incremental updates.
I am not tied to a body. Bodies come and go. I don't care about if the camera is mirrorless or DSLR, I just want the best image quality, at a reasonable price. I would wait for Canon and the 5DIV but I think I will probably buy a A7S or A9 with an adapter when they arrive. If Canon releases a good product by the time I buy a new body, I will go back. Easy. For pro studio shoots, I don't see much an A7 series isn't great at.