I've got an RX-V990 that sounds great in 2-channel mode and, like you, I also listen to music more than surround sound movies.
This site has been rather useless in trying to get info on a replacement receiver that will satisfy. Most of the threads in this particular forum are fanboy threads for a specific model or line and are so long as to be un-navagable . I asked a similar question as yours and got a couple replies and a blatant sales pitch.
For now, I'm not going to change out my receiver. One would think it would be a fairly easy thing to sort out (which AV receiver/s is/are known for their ability to provide satisfying 2-channel performance. I've wondered about a two box solution too but all I've gotten was either confused info from internet posters or sales blather from people who just want to sell something.
Are you able to get any in-home auditions of gear? For me, if I were to buy a new receiver, it would have to be returnable and the first thing I'd do is hook it up to my L/R speaker and connect a source or two to check its 2-channer performance. Only after it passed muster would I connect up the rest to see how it worked as an AVR.
Home Theater: Yamaha RX-V990, Onkyo C-S5VL, Technics, SL-QL1, Celestion DL-8 Series II L/R, NHT center and rears
2-channel living room : Marantz PM8004, Marantz CD6004, Denon DP-23F, NHT SuperOnes
2-channel office: Marantz PM6004, NHT SuperOnes, internet radio fed by iPad Air