It's my understanding that the YSP bars perform best in a room with walls perpendicular to the the speaker bar, rather than at 45 degree angles as in your corner setup. I have a Sony CT500 soundbar and just moved. It's remarkable how much better it sounds in the new space where there are perpendicular sidewalls and carpeted flooring, while my old apartment was open concept with hardwood floors and the sound was quite anemic. In your scenario, I'd consider a passive 3.0 soundbar, AVR, and sub for your setup. If you don't mind cables on the floor or ceiling, you could try for a 5.1 with side surrounds. Using 3 LCR speakers or 2 floorstanders and a center channel might not be optimal with your corner setup.
You could try asking in the soundbar subforum too.