My film AF progression was N8008, F100, F5, F6. The F6 was my attempt to stave off my move to digital which was already well under way when I bought the F6.
My recollections were that the N8008 with 35-70mm f/2.8 and eventually a bunch of AFD primes greatly extended my photography and film consumption. The F100 was by far my favorite AF camera, not because of photography function but because of the combination of function and size. I just didn't know how it could get any better than the F100.
Then came the F5 when the used prices plummeted after the F6 introduction. It was by far my best picture taking machine. The "fatal" downsides for me were the extra weight (offset nearly entirely by the beautiful ergonomics) and the quirky perimeter LEDs that were used to designated the VF AF-sensor coordinates. I pretty sure if the F5 had the F100/F6 red-lighted AF-sensor for low-light photography that I would never have purchased the F6.
For me the F6 also had one very large annoyance and that was the awful choice of CR123 battery power. Just awful. While the F6 was perfect in many ways it redefined the camera platform (larger and heavier than the F100).
My D200 seemed to be a digital F6 when I finally made the jump.
The observation that the SLR was on a plateau that "demanded" the digital age is also the way I see it. That cluster of cameras (F100/F5/F6) had really set the curve, one that IMO we are just now passing with the DSLR.
More AF sensor points and a host of other convenient things are nice, but even the F5/F6 predictive AF engine was no slouch. The F5 power plant could outdrive the F6 in screw-driver focus speed.
Film had some inherent limits on "sensor technology", new R&D may have turned up some "revolutionary" products, but the camera development supporting subsystem development wasn't nearly as tied to evolving film products as with a digital sensor. We are now looking for (and may have just now attained) the new plateau where sensor density/computer-processor/buffer-speed & capacity/memory speed and type will finally reach their realization.
So now that we've seen the future, in addition to the current F6 functionality, I think the F7 will have more AF sensors, all x-type sensors, to the edge of the frame; a current predictive AF system; manual zone focusing/DOF display in the VF; voice annotation; larger exif data recording with more convenient up/down loading interface; leader imprinting copyright and text instructions, profile type, etc. to print processor generated from on-board stored instructions (standing instructions based on film type based with user control prior to load/rewind); higher resolution rear LCD; higher resolution 3D color matrix metering; info button (assignable DOF/ftn buttons); revised interval programming; focus controlled shutter trap/release.
With film evolution that includes a magnetic strip on each leader, much of the exif, frame-related, processing-control information could be added on film rewind/extraction. Given that evolution, also add an enhanced partial roll rewind, re-insert function for ISO changes mid-roll and enhanced printer-profile control. With enhanced exif "magnetic" recording and printer control - lens vignetting control can be applied on printing.