Big bright viewfinders on FF? Just a shame about the one on the 5D! I've seen cameras with smaller sensors that have better viewfinder.....but then the smaller sensor was APS-H rather than APS-C.
For some types of photography I do think bigger formats are better and there are gains in quality to be had but equally I think smaller formats have their uses for smaller subjects. Large format macro doesn't look like very practical for in the field shooting (although for innanimate objects in the studio......)