Thomas Shey
Legend
Yeah, that's a fair summary. If changes are made purely to trick/trap the players, rather than because they make sense for the setting, then it changes the feel.
Also, I'm assuming DMs are not announcing creatures, especially creatures they designed that are seen for the first time, by name. It's one thing for players to assume those hulking, regenerating creatures are trolls. It's another thing for the DM to call them trolls.
Well, that's not an assumption I'd make, and honestly, even the description can sometimes lead that way--trolls in D&D in specific often have a relatively specific look compared to a lot of other large humanoids.
(And this doesn't even get into some other monsters that are much more closely tied to their folklorical precedents in what abilities they have, here.)