In my mind these are two completely different animals. In particular, the RR2150 is primarily an analog unit with the exception of one USB input, while this integrated amp would be primarily digital with the possible exception of either a phono input or just a plan analog input. Also, the form factor would probably be quite different. This integrated amp could probably be about 4"x10"x15"(HxWxD). Plus there is a great deal of circuitry added to the signal in the way of tone, balance, bass boost and bass management all of which adds to the price and does not enhance (probably detracts) the sonic performance.

Now on the other hand, I think it would be an excellent idea to have an updated version of the RR2150 or maybe even a completely new design based on a 2 channel (ok maybe 2.1) primarily digital receiver. Of course I have some thoughts on what that ought to look like as well. Keep the retro look just update the technology inside it, also make it available in black as well. Here would be a good start on the features list.

1) Power should probably be in the 100W area with A+B outputs
2) Reasonably good DACs of course.
3) The price point will have a very larger impact on the quality of the DACs and amp. I'm not sure where the sweet spot would be. Me personally I would pay up to $1000 if the DACs and amps were right.
4) A good variety of digital inputs, 2 USB, 2 Coaxial, 2 Optical and maybe even an AES/EBU
5) A couple of analog inputs and a phono stage as well
6) Internet connectivity with various streaming services supported
7) Bass management for both the A+B sides with two sub outs (one for each or both for A depending on selector switch)
8) Digital direct mode, i.e. Source input -> DAC -> to amp -> Speakers (Thats for the purists!)
9) A good display that can be read from a distance, but dimmed when not needed.

I don't know how many of the RR2150s they sold. My impression was that it was popular. A new version would be every bit as popuplar and possibly even more so.