You mean like they did with the 30D after the D200?

Yeah, that
was an AWESOME answer...
IMO, as a fairly new and not very brand biased Canon 5D-user, I
think Canon should start looking at the competition a bit further
beyond high ISO-performance. Tried a friends D200 last weekend and
was impressed by all the, for me, useful features like for instance
the possibility to get blinking highlight for the separate
RGB-channels to show channel clipping.
Love the performance of my 5D and I don't mind if Canon keeps the
5D house, but as a software engineer and GUI-designer myself, I
think they could do so much more with the current platform by just
adding features to the cameras software that makes sense for
digital photograpers and give more control to the photographer.
Auto-rotation ala the 30D and programmable auto-ISO ala D200 would
be a start. You shouldn't have to buy a new camera just to get
software updates. On a whole I still think modern DSLRs are
crippled by thinking based on/inherited from traditional SLR
technology.
cheers.
daniel.