Tony Vargas
Legend
There was a lot of hand-wringing back in the trenches of the edition war about 'play style,' something that had hardly ever garnered comment in the past, but no, that's just begging the question: both are subjective and don't address the actual differences.I imagine the emotional "this doesn't feel like realz D&D!!!1" reaction is a reflexive way of trying to express "well, these rules don't quite fit my play style, that's unfortunate."
Both are also emotional appeals at least as much as emotional reactions. One accuses the game of betrayal of an ideal, the other, even less credibly, of persecution. Maybe there were some emotional reactions being expressed, maybe there was some calculated manipulation going on, probably there was both and they could end up looking pretty similar from the outside.
3.x managed no such thing, not even close! Fans of the classic game were already chaffing at the player-focused attitude of 3.x (it wasn't as dramatic as the edition war, but there were just as unfounded criticisms flying at 3.0 from the beginning, just not from such committed partisans), and the way it supposedly* undercut one of the two styles (that pemerton articulated, above - the second one, in case that's not obvious) for which the classic game was suitable (even as it's system-mastery-rewards opened up a couple of new player-focused styles, optimization** and PvP, for instance). 3.x was different from the classic game and from 4e, but it's community was far too RAW-obsessed, and its mechanics too imbalanced, to be used in wide range of styles - it didn't manage the little bit of legerdemain that 5e did in getting the community back to trusting their DMs to take the game in other directions, whether with rulings or modifications.That can be pretty jarring if your play style is your wholr experience of D&D, and 3.x warts and all managed to be a big tent for play styles, if nothing else...
I suppose that the 'style' thing might have been silently building up over the editions. AD&D was different, arguably more simulationist, I suppose, from 0D&D, and Arduin purported to pick up D&D's true legacy, 2e tried to be more story-oriented even if more in presentation than mechanics, 3e was more player-oriented, 4e better balanced. Each of those shifted the focus of the game around. Arguably, once the idea of a playstyle was articulated, you could say that those different focuses 'supported' (or over-rewarded, or forced) certain play styles.
Though, 'support,' as our conversation has illustrated, can be a tricky idea. You, for instance, clearly feel that no mechanical tools at all constitutes 'support for TotM' in the case of 5e, while the presence of better tools for minis & grid does not in any way take away from that support for TotM in 3.5, yet slightly more streamlined mini/grid tools make TotM impossible under 4e. So, yeah, 'support' can be a fraught subject.
(And, yes, that inconsistency in opinion perhaps comes down to the original 'feelz' idea.)
Anyway: Style. To the extent that it's a thing influenced my system, style can be rewarded, allowed, or penalized (and the line for supported might be subjectively drawn anywhere along a continuum including those three). If a system is hypothetically style-neutral, you /can/ play it under any style, but there won't be a tendency for a certain style to develop or be hard to maintain because of the system, rather, play will naturally tend towards whatever style(s) the players prefer. If a system rewards one style over another, play will tend to drift towards the favored style if it's compatible with the preferred style of anyone at the table, at all.
If you want everyone playing in the same style (at your own table, not an unreasonable thing to want), without using social mechanisms (like, oh, talking to your players about it) to make that happen, picking a system that over-rewards the desired style and punishes others would be helpful. If you've been doing that to good result for a long while, and change to a system that doesn't favor that style as much, even allows more alternate styles that were never really in the running, before, then you might be shocked to see play drifting away from your preferred style and towards those that, perhaps only out of novelty after playing in the system-favored style for so long, appeal to other players.
You might then say that the new system 'doesn't support' your style of play.
One quality that makes a system suitable for play in a wider range of styles, by virtue of not over-rewarding one or disfavoring others, is, of course, /balance/.
* it's not like 3e set out to dis-empower DMs, it had Rule 0 right at the front, and nothing the /system/ could do could prevent a DM from overruling or modding it. That credit has to be shared with the community groupthink that rapidly developed around it.
** calling optimization a style maybe does both terms a disservice. Optimization can be used in the service of player-focused styles, whether that's by using it to the game a chargen or paint a detailed picture of a character or whatever quality you're optimizing a character for. It can even be an enjoyable (meta-) game in its own right.