paul, as others have said, you have great gear already
your room is probably what is holding back the sound the most, but you have stated your reticence to treat/alter
given this, you would need to speak precisely and specifically about what you would like to improve about the sound as it stands now, to get any useful ideas on what to change in terms of the hardware
you mentioned occasional brightness, but how occasional, and how troublesome? b&w's will give you that sometimes, no doubt
your room is probably what is holding back the sound the most, but you have stated your reticence to treat/alter
given this, you would need to speak precisely and specifically about what you would like to improve about the sound as it stands now, to get any useful ideas on what to change in terms of the hardware
you mentioned occasional brightness, but how occasional, and how troublesome? b&w's will give you that sometimes, no doubt