I, at the moment have 190 hours clocked on Steam and I have to admit that after some time the game gets really boring and repetetive. Radiant quests killed the fun of getting and completing a quest, main quest is honestly not that interesting (hurr durr we have to kill the big dragon) and the game world is honestly a mixed bag in my opinion (while it has more detail than Morrowind and Oblivion there are mutliple points where I prefer the world building in either of those games over Skyrim's).
While I completed the game several times without using any mods, I have to admit the mods do make the experience more enjoyable (to some degree). Granted, by using mods you adjust the game experience more to your taste but I didn't feel the same need with Oblivion and especially Morrowind.
If you guys disagree or have anything to fill into what I just typed out here feel free to let me know, I'd love to hear some new points about this issue.