1) I find this idea aesthetically unsatisfying.
A lot of monsters have great names! Goblin. Elf. Troll. Dragon. They’re good words, loaded with resonance. The fact that they conjure immediate associations in the listener is a good thing.
2) I have tried this and it didn’t work.
In my most memorable attempt, I ran an encounter with a gold-chased, gem-encrusted minotaur skeleton without ever saying the word “minotaur” and my players thought the fact that I scrupulously avoided saying it was a joke. Maybe this is a bad example because skeletons and minotaurs are such identifiable monsters compared to the various shades of goblin/hobgoblin/ghoul/orc that people typically use as examples for this principle, but I ended up using a lot of words to zero benefit. That same dungeon also had undead monks who had had the first joint of each finger cut off and replaced with pen nibs, fought in a ruined library that was knee-deep in foul water. That encounter had a much bigger impact on the players and it didn’t seem to be lessened by the fact that I mostly said “zombie” instead of “dead men, rotting yet still animated by a hideous spark of unlife” when one of them made an attack roll.
This admonition, I think, comes from DMs who love running gonzo horror games, where it is genuinely a great piece of advice. It is a little deflating to learn that the braying horror that Cletus Clanghorn just fired his last shotgun shell into was actually a cleverly-disguised bear. But not every palate is so jaded, and in a more classic fantasy milieu you can easily find yourself obfuscating to no benefit.
Can you imagine trying to describe what a dragon looks like without using the word “dragon”? Do you think your description would be enhanced by that omission? If you spend a lot of time describing a “lizard-like creature with four legs and vast bat wings, with smoke curling from its nostrils” your players will probably go “...so is it a dragon?” Whereas if you say “a delicate pale-blue dragon with silvery wings” (or indeed "There he lay! A vast red-gold dragon, fast asleep") the word “dragon” is doing a lot of heavy lifting that opens up more space in your descriptive budget. By not hiding the ball on what it is, you can spend more time on what makes it interesting.
3) Metagaming Concerns
Dungeon of Signs says “...the specific mechanical aspects of a potential foe is the last thing one wants players to be thinking about when they start an encounter.”
This is, in my experience at least, wildly untrue. Players love thinking about the specific mechanical aspects of a potential foe! It’s part of how they assess the risks of an encounter. This isn’t to say you should just hand your players the relevant monster manual page for each fight, but informed decisions do lead to good gameplay. Many of my formative D&D memories involve one of us kids eagerly sharing some monster facts and discussing strategies for how to deal with them. Some of these schemes were good and some were terrible, but they were all engaging. You can decry this type of out-of-game discussion as metagaming, but I think the sense of shared adventurer knowledge is a lot of fun.
Por Que No Los Dos
Outside of gonzo-horror reskins, I think there is a useful nugget at the core of a lot of the Never Speak The Monster’s Name advice, which is just that monster descriptions should be evocative, and that your players should have reasons to care about them. I think it’s perfectly fine, even good, to use monster names paired with a good description. For example, Against The Wicked City’s ogre description reads “An eight-foot giant who comes clambering from her cannibal larder, her hot breath reeking of carrion, her long hair matted with human gore”. In a setting where ogres aren’t a discrete category of monster and you’re just using the stats to describe some kind of human mutant, great. In a more typical D&D Fantasy setting, I don’t think it would be at all lessened by changing it to “The ogre comes clambering from her cannibal larder, etc.,”. You get the associations of the word “ogre,” and have now tied it to the specificity of what this ogre is like. It’s notably a different kind of ogre than an oafish, fur-clad, treebranch-club-wielding ogre, emphasizing different qualities of the name’s common associations. That sort of thing builds the space of the imagined world: if I meet a goblin in the same setting as the cannibal ogress, I’m not likely to assume that it’s the silly Labyrinth variety. Finally, some of this is mechanical. If goblins are a worthless chaff enemy, then your players are unlikely to care for a long description of what is essentially useless information. If on the other hand the arrival of 2d6 goblins is a meaningful encounter, then I suspect that they will!
If you're a bad enough dude, you can give a monster plenty of impact with no description at all.
"Thus he came alone to Angband's gates, and he sounded his horn, and smote once more upon the brazen doors, and challenged Morgoth to come forth to single combat.
And Morgoth came."
Postscript: The Wisdom of Solomon
If you’re really bothered by D&D taxonomy of humanoids, however, and are determined not to tell your players which Monster Manual entry you’re referencing, I recommend a compromise: lump your categories. Kobolds, goblins, hobgoblins, orcs, and bugbears can all be “goblins”. “A huge goblin, almost man-high”. “Shaggy-furred beasts with long arms and horrible goblin faces”. “Squealing goblin imps with beetle-black eyes in their spoiled-milk faces”. Ogres, trolls, giants, and so forth can all be uh… one of those things. A huge range of creatures can fall under “fairies” or “elves”. Basically every corporeal undead can be a “revenant,” “wight” or even “ghoul”, and the incorporeal ones can equally all be “spirits,” “ghosts,” or “wraiths”. Each of these choices will skew the flavor of the monsters and setting in a certain direction, which you can use to your advantage – see the shift from “goblins” in The Hobbit to “orcs” in The Lord of the Rings when describing the same creature.
