I guess I don't see how "have it use much weaker option A instead of strong option B so an extreme roll doesn't mangle things" is tons different from "rolling two smaller dice than the two big ones called for" is tons different from "fudging the die rolls so they don't exceed what the two smaller dice would have done".
But if I had a player who hated one of those I would avoid doing it if there were other options when it seemed called for.
Well, if you want my answer (which need not be anyone else's answer):
Tactics are not something well-defined within the rules. The fictional positioning and situational status of entities in the world are within the player's purview: a regular player plays their PC with whatever attitude they desire, within the limits of decorum for the group, and a DM "player" plays NPCs and opponents likewise. Why does a monster choose to ignore the downed Cleric and focus on the Wizard nearby? Because it has some reason to--perhaps the party can figure it out, perhaps they can't, but the
act of choosing to do that is obvious to everyone participating. There's no secret, hidden choice that makes it
look like the monster is actually targeting the Cleric when they're truly targeting the Wizard. There is no difference between appearance and (fictional) reality.
I'm afraid I don't really know precisely what you mean by the smaller-vs-bigger dice, but I'm going to assume this is (for example) choosing to roll d4s when a monster crits instead of d12s or whatever. My issue here is that this takes away the stakes of play, in a way the players cannot see or learn about, but which actually does affect the consequences of their actions. It is the DM interceding in the connection between "player made unwise choice" (even if that unwise choice was "trusting the dice too much") and "player suffered a negative consequence as a result," in a way that cannot be learned from. The player will construct false "knowledge" from this, believing they've learned about how the game works, but actually only learning "the DM will interfere when it suits them to secretly protect us from the results of bad decisions and/or protect our opponents from unexpectedly powerful results." That
does not mean that DMs shouldn't do something to address problem cases! It means that they should not
pretend these consequences are what follow from the choices made, whoever made them. Both DMs and players learn by facing the problem and addressing it, rather than sweeping it under the rug and pretending there was never a problem to begin with.
The latter is just pretending you run a game by rules and instead running it by whim. In that sense, it's not actually much different from the preceding example; the previous example just puts in an intermediary of choosing smaller dice by whim, rather than choosing the smaller result directly by whim.
The thing is, you can get
all of the benefits of fudging in this way, without ACTUALLY fudging! You can have your smaller dice, or even your chosen result if that really tickles your fancy,
without preventing the players from ever knowing it. Instead, you make the change
diegetic. Something--perhaps even you don't know what!--
prevented the damage from being as much as it should be, or narrowed the range, or whatever else. That something is real, and at least for combat stuff, most characters should have some idea of the fact that a blow didn't hit as hard as it should have or didn't swing as far as it should have or whatever else. That's a clue that something hinky is going on. The players may ignore it, or they may fumble their investigation (because that happens sometimes!), or they may draw erroneous conclusions about it--all of that is perfectly fine,
as long as they had a legitimate chance to learn.
Which is why I say there is nothing productive you can do with fudging that you can't do
without fudging. Because the only things you can do with fudging that can't be done without it
directly depend on ensuring the players cannot even in principle know that something happened. The only time fudging is
required is when
deceiving the players is the whole point. Everything else can be addressed some other way.