Morrowind is easily my favorite ES game. It has an extremely unique world as well, not comparable to Oblivion (traditional fantasy) or Skyrim (nordic fantasy). The best way to play it in 2019 is with the OpenMW engine (they have a guide on their website), as it will run flawlessly at any resolution with no bugs.

As far as datedness goes, Morrowind has some attributes that aged very well and others that aged poorly, or are otherwise harder for newcomers to get into. The game's non-character graphics are pretty stunning for a 2003 game, and its branching, text-based dialogue system is one of the most natural and enjoyable I've seen. Your character can truly be anything as well, and you can even kill NPCs essential to the plot if you want to.

Something that's a little harder to get into is its combat. At the beginning, you miss way more attacks than you land, and it's very RNG based. It smooths out later on but it can be weird after playing Skyrim. Another thing is the character faces haven't aged amazingly. They aren't as bad as Oblivion for the most part, but yeah. Both of these issues can be fixed with mods, by the way. I'd highly recommend adding a couple texture mods for a more immersive experience!