easy shit like rpg, stats, character/class creation..boring... the world building? other people have said enough before... we know it's good,..
stuff I like:
you can fail at things. miss attacks, whiff spells. lots of dice rolls behind the scene. combat and actions are not just "be good enough as a player to execute" but also have luck. as your character improves you can more reliably do what you want to do.
the world is full of stuff. there's stuff everywhere in morrowind, plates, mugs, books, shirts. this is the same in later elder scrolls but that stuff doesn't have VALUE; there's no point picking up plates in oblivion. but in morrowind Stuff has value, people buy it, people sell it. you have no use for a knife and fork but someone in the world does, so people trade in cutlery
you are embedded in the world. you can only fast travel by engaging with the world (boats, methods of teleporting, etc). you can fly into cities with no city wall to pass. to navigate the world you talk to people for directions, look and signs and landmarks. many (not all) parts of the world do not scale with your level. the endgame dungeon is there at level one and will kick your ass if you try.
dialogue is topic based, freeform, often not a branching tree. if you don't know what to ask you can't ask it. conversations are like wikipedia pages until someone else asks YOU a question, when it becomes branching. not everyone has something interesting to every question, but you can try anyway.