I guess some folk may actually prefer imaging for the "illusion" since that is all that reproduction is, right... creating an illusion?
Others might prefer "presence". I personally like imaging becuase it makes the vocalist or lead instruments appear more centered, and lends to the illusion that there is a real instrument playing... centered somewhere. Of course, you & Wayne are right: in a real performance, especially one that is electronically amplified, the singer's voice or lead instruments' notes will come from all over. However, in an unamplified performance, with a well damped room, the singers voice and the instruments should be localized, even in a live performance, no?

Based on the above discussion, perhaps imaging is good to create the illusion of a live umaplified performance, even if it were not really that way. That's probably one of the reasons why so many folk like single driverspeakers that image so much better (beaming etc) when listening to small arrangements (like one singer and 4-5 instruments).

Keeping the room treatment constant, it makes intuitivie sense that speakers with higher directivity will image better. What do you & Wayne think?

-akhilesh