N70 and N80 were different generations with some BIG improvements (and some losses).
Speculating on a D80, is in my opinion, a futile act. Nikon will do what Nikon want to do.
Having said that, here's what I'd like to see:
1) Bigger viewfinder. 2) Ability to use a cable or electronic release. 3) Battery pack for additional mass for increased battery time/better handholding. 4) A vertical shutter would be nice, with command and subcommand dials, but is not necessary. (Hey you gotta keep costs down, right?)
Nah, it'll bet my two bits that it'll be called the D90.
I think that it would be in Nikon's best interest to keep the names between the film and digital bodies staggered... otherwise, people make automatic parallels between similarly numbered units.
Look at the fuss that people made over the D100 vs. the F100. "It's not up to an F100's build quality." "It's not a professional body like the F100." "The D100 is based on the F80, so why isn't it called an D80?", etc. etc.
1. Multiple custom tone curves storage and selection 2. Upgradable CCD to have more pixels - insane am I 3. RF remote shutter instead of IR 4. Stronger AF asistance or better AF sensitivity. It sucks that you wife keep nagging missed perfect smile on the kids while the Lens struggling finding the face 5. Include focus distance info in the EXIF info
IMO focusing distance information would be of very little use. It is too discrete - the lens actually only reports which of the few "zones" it is focused into. They may be like five or ten, which is quite enough for flash calculations but what else would it be good for?
Actually, it should be easy for the camera to report the focusing distance if you are using a D or G-series lens because it reads the position of the focusing ring (and therefore the distance of the subject). Unfortunately, if the lens is focusing at infinity, you won't get a meaningful number.
...there's always room for improvement. Let me just say I'd like it have a dedicated timer mode. Not the one that cancels itself after each shot, or the 15 minutes limit when using ML-L3. It could use a better view finder and faster/more sensitive AF module. Dedicated flash setting button. Threaded shutter realse would be good.