The later the expansion, the less I enjoy TW. Why? Because later dungeons just had to add annoying mechanics or gimmicks to stay "interesting".
I've only done 1 Cata TW this week and I ended up getting End Time, which I dislike. I, too, thought it seemed harder. But regardless I just don't like the dungeon. I also dislike Throne of Tides.
The Shado-Pan Monastery in MoP is annoying.
Grimrail Depot in WoD is annoying.
Court of Stars in Legion TW can bite me. I've reached the point of just leaving the group and taking the deserter buff if I get this dungeon.
Even in WotLK TW, I don't like Pit of Saron, partially because there's only 2 bosses.
Also, there are scaling problems all over the place. The 2nd boss in Gundrak at 10/11 can hit you for 70% of your health. I started switching to Prot Warrior just for this boss because you may accidnetally die if you don't.
Not TW but this happens in Hellfire Ramparts too. Vazrudon has an ability that'll do 500k+ damage to you if you're 10/11 (you know, with 2k health).