That's just, like, your opinion man.
It consistently outsells all competitors. I love all kinds of tabletop RPGs, but when it comes to medieval fantasy dungeoneering D and D is where it's at. :mohawk:
It was remarkable in its day, back when it was pioneering a new genre. Even then, though, it was NEVER a "medieval" game, and never had anything even remotely to do with realistic combat mechanics or rational tactics or strategy. It's pretty obvious that the designers knew nothing about ancient or medieval combat, weapons, or armor, but made an amusing and entertaining game system in spite of that. Unfortunately, a lot of the original design limitations and absurdities became rigid stereotypes, and it gradually turned into little more than a bad caricature of itself. The collection of talented artists and story-writers who became involved with it have managed to keep it alive, long after the stale game mechanics should have given way to something much better. At this point, I'd suspect that the biggest thing holding the game back is the game itself.
Personally, I think that Bethesda has gone far beyond what D & D is or was, as have a number of other computer-based and pen-'n-paper RPGs.
To me, about the worst thing Bethesda could do would be to lean the game back toward its pseudo- D & D origin.