The best description of Morrowind, Oblivion and Skyrim I've heard is:

Morrowind is a book (with fantastic illustrations). There's a lot of reading. There's a lot of filling in the gaps with your imagination (combat). This can make it harder to get into, but when you do it's a deeper experience and timeless.

Oblivion is a community theatre production. It's kind of a hot mess and the acting is terrible. But you can still feel the love it's creators put into it, and it's charming in weird ways you'll remember forever. But you don't want every experience to be like this.

Skyrim is a blockbuster movie. It's initially really fun and climatic, but the more you revisit you see the plot holes, the limitations of production, the recycled tropes etc.

The Dark Brotherhood questline kind of pisses me off, or at least the second half does

I was pretty close to finished, but one of the last quests having a totally deflated final showdown between two factions where a dozen guys showed up and hit each other with poles in a courtyard just made me do the other stuff but none of it really landed for me.

Jokes on you, there are no polearms in the game without mods