Just installed Morroblivion, been playing for 15 minutes.
In that time I've managed to be unable to sell "stolen" items to a vendor, and tried to kill two "essential" NPCs.
Which is kind of weird because I don't remember those "features" being in Morrowind.

True you could do that in
True you could do that in TES3, but is that what really made Morrowind, Morrowind?
I'm not sure if these are limitations of the Oblivion's game engine, but if it's possible, you could look into fixing these problems.
Edit: That's how I started here. Without the TES3 voices, it didn't really feel like Morrowind to me. So I fixed the problem and put the original voices into Morroblivion. A lot of other team members here have undergone the same thing, and that's how Morroblivion gets better and better.