Recommendations Wanted

Some recorded music, when properly reproduced, will make the loudspeakers disappear and generate a convincing facsimile of the original recording space, but other records cannot.  It has to do with how the music was recorded and your system will not compensate.

BTW, I like your system.  Others are in a better position to recommend a replacement for your B&Ws.

FWIW, I see what I believe to be other weaknesses in your system besides the speakers. IE, you have no sub listed. That may be what you need to make those speakers sing. Two is better. But It will make your mains sound much larger with a bigger sound stage. There is another item I might change also. But not the speakers until you try a sub, preferably REL IMO

That said why do you think your speakers are the weak link?

Triangle Esprit Australe EZ if you can find a pair. They love tubes and are masters of 3D sound. 

You don’t mention room treatment, that can play a roll. To the above, some music is just not recorded or reproduced in great quality. Look into room treatments, find a song or two that gives you what you desire, move your speakers around a bit. See how that changes the stage. Sometimes micro movements can make all the difference.