The first reason is Draugr. I hate draugr dungeons. It seems like 80% of Skyrim dungeons is going through yet another draugr dungeon that looks the same as all the previous ones and has the same looking enemies with different names. I understand that draugr are to be expected in Skyrim but there are just way too many draugr dungeons. Also the dungeons are so linear. Fight through a bunch of weak draugr while following the only obvious path until you find a hard draugr. Kill it and look for your loot chest and then leave by way of the secret exit.
Another reason I feel Skyrim has weak dungeons is the lack of hand placed amazing loot like the artifact rings in Morrowind that you could stumble upon in burial urns. In Skyrim you can find, if I recall correctly, around 13 gold and maybe a gem in urns. Hand placed artifacts gave the dungeons a sense of uniqueness and adventure. You never knew if this dungeon you just found might have an artifact lying around. All the artifacts in Skyrim are recieved through quests afaik. Also in Morrowind there were hidden daedric items and other valuable things lying around and not just randomly generated in the boss chest.
When I play Skyrim I get the urge to just sprint through dungeons until I reach the end because I know the only good stuff will be in the boss chest. Also because I hate draugr and don't want to waste time swatting them. Anyways I feel like this game is a step backwards in the dungeon department. Feel free to post that you disagree and why but don't make any attacks at me because of my opinion. I am not a Skyrim hater. I am just a bit disappointed with parts of this game that could have been better. Btw Morrowind is my favorite game out of the three.