There will never be an FF body with D300/7D2's features at 1,700USD. The disposable income distributions curve (for individuals and small businesses) for cameras is, I bet, already in the right end of tail at that value, so a D810 is totally out of question for most (think budding pros, schools, universities, architectural offices, etc).
For starters, it's $1799 USD, not a hundred less than that. Moreover, I believe you are already above the price that might be comfortable for most non-professionals. We'll have to see. Secondly, I think full frame is the way to go for the more serious users for a number of reasons. Only the robust build comes to mind as important in my world as well as other jobbing professionals I know.
As far as a "budding professional" is concerned, I don't think it's wise to strap oneself down with a small APS-C sensor unless you really have to for some reason. I can think of no features in the new Canon or imaginary Nikon D400 other than build quality which I'd consider to be important enough. Being able to shoot RAW with a full sized sensor is just about the most important feature possible. I'd rather see the compromise be in build than sensor size all day long. This means seeing our budding professional using a professional size format. In other words, I'd much rather see them beginning their investment with a D610 than some loaded with whistles and bells small format body.
Those whistles and bells are features you don't need or use much as you grow out of beginning photography and into professional usage. What's the point of fancier matrix metering, if you learn to avoid Automatic Mode? When I say Automatic, I mean all the automatic modes from Aperture Priority to Green Auto.
Your budding professional should probably invest slowly and carefully in pro-grade glass. There are only, at this level, Nikon with the 17-55 and the 12-24 which I know of. The rest are all designed as FX offerings. They can be used on DX, of course, but where's the advantage?
DX is supposed to offer us size, weight and price savings, right?
Again, we'll just have to see. I'm not sure where you're getting all this about universities, architectural offices and the like, but I certainly don't agree.
Anyway, take care.