One thing that hasn't been mentioned about LCR panning in the early days of stereo is that the early stereo desks/pres often didn't have pan pots, they had three-position switches marked L C R, so the only options available were hard left, hard right and centre.
Hence the recordings of the period with the drums panned hard right, vocals center and bass and guitar hard left when mono would have sounded far more natural (and usually better).
I'm with Jonbouy on this - panning isn't just there as a way of setting out a "fake stage with a band on it" or separating things out in a mix (eq can often do that better in any case), it can be a useful and powerful sound designing tool and effect in it's own right.
An autopan plugin containing an LFO or two with a variety of waveforms is something Sonar could really do with in my opinion.