I probably have a tendency to abuse my M/S more than is healthy, but I see all of this as a question of intentionality: If stereo is treated as a superficial afterthought, rather than a furtherance of creative intent, then mono is always going to seem the more pure or authentic approach.
This discussion reminds me of some notions I’ve been entertaining in regard to chipmusic: Implicit nuance in music figures in heavily when dealing with archaic PSGs, particularly in their original context. For instance, I came to love the sound of the Gameboy mostly through its dinky little mono speaker, but I eagerly indulged the occasional use of crumby headphones for its limited stereo capabilities. I couldn’t say offhand how much the Gameboy’s hard-panning capabilities figured into the compositions I most enjoyed, but it did feel like I was tapping into a rather unique musical space. Yet the bulk of that uniqueness was less attributable to any objective nuance of the Gameboy’s sound capabilities than to its quirky constraints and the intentionality behind the compositions created within those constraints (not to mention the emotionally loaded medium).
The appreciation of chipmusic is rather esoteric and by no means uniquely a result of any explicit quality of the sound (outside of its recognizability). I’ve since come to appreciate the juxtaposition between chipmusic in its purerer form (as directly played back through original hardware or emulation, particularly in the form of VGMs) and chipmusic which has undergone more deliberate processing (as opposed to a merely cosmetic treatment), to include widening or blurring the stereo field, deepening and parsing out its spectral character, clarifying its distinctive voices, or what have you.
These days, when I’m producing PCM from chip-based sources, my goal is to explicitly flesh out my impression of the original sound in its more constrained context, and if I were to limit myself to the use of mono or some merely centered spread of its original stereo character, I would be eliminating a great deal of intentionality therein.
I’ve approached a number of old lo-fi monaural session recordings of mine in similar fashion. It’s just a way of imparting my more idiosyncratic appreciation of the original in a more explicit fashion (or as well as I’m able, at least). This gets us, I think, more to the point and into implicit vs explicit spatial and dynamic character, since in a mono mix, you can only ever achieve an implicit sense of space and likely lean heavily on dynamics to achieve this; but there’s nothing preventing a stereo mix from taking either or both approaches. For my part, I almost never use dynamic panning (only one instance I can think of where I have, and that was performed on a 4track) and I’ve only lately begun to apply dynamic modualtion to PEQ in M/S, but my habit, taste, or whatnot has typically been to achieve spatial dynamics as implicit to how a mix’s spectral character plays out across the stereo field.
All this said, sometimes mono is what you want to get across or is particular to the medium you’re producing for, but I would generally reject any enjoinment to prioritize mono at the expense of stereo (either embracing or rejecting stereo as so much garnish), though obviously one ignores mono at one’s peril.
While I prefer working almost exclusively in M/S with my electronic stuff, I always eventually have to consider the panning (which, granted, can simply be handled in M/S gain-staging) and occasionally have to flip my stereo buses to balance things out for just this reason. Plus, there’s hardly any other way to go on a 4track as I’m often wont to use, so even if I end up handling the discrete tracks through M/S, it’ll typically be in parallel with the panned mix, which tends to curb at least some of my M/S abuse.