I'm moving to R8070. Besides styling and the "shadow" rear derailleur arrangement, 8070 has the shift/computer control buttons on top of the hoods, a 34T rear derailleur capacity, and designed-for-the-road disc brakes. In my case, I'm changing bikes to get road disc brakes and the other perks are an added bonus.
Since they are all eTube, I would be very surprised if the older shift controls can't be programmed to operate the new derailleurs. And shift speed? It's programmable on all Di2 derailleurs. You can have whatever you want. But that's nothing new.