I'm not whining. Don't get that idea.
The one person who sounded truly determined to try out the game features that were important. The one person out of how many? 100? Tops? The rest of whom didn't get to that area of the map. It's not like it was next to Riverrun. The first guy that got over to that area found it.
and it didn't sound particularly well hidden. It will be visible from the other direction, don't forget. Well hidden is in the basemant of the spell merchants in a major city, with the building located in the busiest part of town. Not in a door in a mountain that screams "OPEN ME!" to anyone near that pond who can see it.
But is this dumbed down? if you get the quest from the dark brotherhood you would be told what to say and it's exact location, well hidden or not, and if you don't have the quest than the door hiding is rather kind of unimportant since if you find it, then what? could the guys who found it open it? no, they didn't even know what it was. It sounds like you say it's dumbed down because it was not well hidden, as in, they purposefully made it easy to find, but what would be the purpose of finding it easy? you can do nothing if you don't have the context sensitive information to break the riddle, the players don't even know what the door is about, and if you have the context sensitive info, you would have been told it's exact location anyway, leaving it's level of disguise irrelevant.
I don't think this is dumbing down, because there's nothing to gain from making it easy to find.