The width of the baffle really only affects the baffle step. If the crossover designer knows what they are doing, there is very little difference. Having chamfered edges or a curved face (like the LS50’s) have a bigger impact than the width of the baffle (assuming equal efforts of dealing with the baffle step).
narrow and wide baffles and imaging
According to all the "professional" audio reviews that I've read over the last several years, narrow baffles are crucial to creating that so-desired pin-point imaging.
However, over the last few weeks, I've had the opportunity to audition Harbeth 40.2, Spendor Classic 100, Audio Note AN-E, and Devore O/93. None of these had deficient imaging; indeed I would go so far as to say that it was good to very good.
So, what gives? I'm forced to conclude that modern designs, 95% of which espouse the narrow baffle, are driven by aesthetic/cosmetic considerations, rather than acoustical ones, and the baffle~imaging canard is just an ex post facto justification.
I can understand the desire to build speakers that fit into small rooms, are relatively unobtrusive, and might pass the SAF test, but it seems a bit much to add on the idea that they're essentially the only ones that will do imaging correctly.