I've mixed views there.
I spent a lot of time on Oblivion and Skyrim, but Morrowind just felt more memorable. There was something about just how different it was that made an impact.
In terms of raw gameplay, Skyrim and oblivion have it beat, but in terms of setting, story and depth? There isn't even a competition - Morrowind is still the outright winner.
They built a "back door" to finish the final quest for murder hobos. That's real choice.