I love doing some of my mixes in LCR only. It really depends on the type of music, how dense the mix is, etc. but it can most assuredly sound great in both mono and stereo.
I mix on my nearfield JBL LSRs and a mono Mixcube, and only reference my headphones occasionally towards the time I feel almost "done" with a mix. I have never heard any "issues" that sound odd. I can however, quite clearly hear instruments in their own space in the mix every time. As I stated, this is wholly dependent on what your end results desired are as to whether or not that's a "good" thing to have everything clearly defined in their own space. some mixes benefit from "bleed" and those are the mixes that I will send a mono guitar's delay to the opposite side of where I pan the guitar. Usually, those mixes are the "lighter" ones for me that are not quite as densely populated by multiple elements playing at once, 2-4 elements. I find when there are 4-5 and up elements playing at once with things like "pads" and "fills" etc being played it's easy to give everything space with LCR panning.