I know what you mean, folk were never going to be happy with the M unless it AF'd better than their 5D3s had more dynamic range than drum scanned velvia 50 rollfilm and took FD lenses (one of the more out there suggestions to fix the M)
So to but a further spin on the curve ball, what features does your DSLR have that you would
I agree with most of these - but then again, mostly this is software. Having it or not having it makes no difference really.
GPS on bodies like the 1D or 5D series makes no sense to me, either - is there a pro here who is actually using that? Do you then look at the pins on iPhoto to see where you had your shootings, in case you forgot?
And yes! The print button! I have been wondering about that thing since I got my first DSLR (the 10D) and am annoyed that I can not reprogram that button... But maybe someone is really using that - since you can do in-camera raw-editing now (another feature that is utterly useless to me).
I really am waiting for someone to request the 1D to accept a SIM card for image transfer via LTE. It would add the very useful feature that you can also use your camera as a phone! And since it will have a retina touch screen and accelerometers, you can also play doodle jump and angry birds on it! And since taking pictures is so utterly boring, this will finally also allow us to watch movies while shooting!
((Just to be clear, and since I know that someone will point that out - I am aware that the 10D does not have the print button, and when I had it there was no pictbridge functionality. But I hope you got the point...))
On a more serious note - better sensors (higher DR, less noise) are always nice, taking noise-less pictures at 1/2000 and f/8 with no light certainly would be fun. Doing 60 fps raw without ever filling the buffer would be good. This is where it will go, I don't think Canon can beat the speed of technological progress.
Then again, and this has been said above, to take nice photographs one normally can do without such features. Sure, modern cameras can capture moments that they could not 100, or even 10 years ago. On the other hand there are many features that really do not contribute to the quality of a photo at all, like GPS or retina displays. Some people might use and enjoy them, but they do not make a camera better or worse, they don't even allow you to do things you could not do before.