I felt Oblivion had more playability than Skyrim. Like Cog said once you maxed out the skills you used it lost is charms. Even modding it doesn't help. Hell I enjoy making/installing the mods more than using them.
When Skyrim first came out it was awsome but I felt it was lacking depth in its quest lines.
I completely agree with this. Even after the main quest and guild quests and all the side quests in Oblivion, I still had a blast for a long while after and continued to play and find delight in it.
With Skyrim I feel like the quests were much shallower and less developed. I've done
most of the quests in Skyrim, but still, it just doesn't have the draw to make me want to go and do
all the quests.
Skill-wise, I was disappointed a lot by smithing. It was beneficial as it allowed you to improve your armor and weapons, but it took so much time and effort and (in-game) money that the payout seemed miniscule by comparison. And once you reach 100 woohoo you get Dragon armor which is fantastic but after you smith your dragon armor then what? You no longer have any sort of direction to it. No further ways to use that skill and interact with that facet of the game. Forges are useless, workbenches are useless, grindstones are useless. All of that effort you put into it becomes obsolete.
The same goes for most any skill. What happens when you've done all the quests and maxed all the levels? There's nothing more to do. Sure, it tries to keep you entertained. There's a technically limitless supply of quests in Skyrim, what with the Radiant system that keep creating quests as you need them. But these quests are silly and trivial and follow a cookie-cutter sort of approach where the details are changed but the basic structure remains and everything lacks depth.
Mods even become stale after a while. Most mods I've seen are new armors, new followers, new textures, new structures, etc. Nothing that
truly enhances the playing experience or increases replay value.
By the end of my time playing Oblivion, I knew almost all of the quests by heart and I could predict from memory the exact words of NPCs during certain scenes. I got most of my entertainment from the game by creating new characters of different races, classes, and the like and creating their backstories in my imagination and giving them unique personalities. The game itself had very little to do with my entertainment at that point.
Now much the same has happened with Skyrim. The problem, however, is that comparative to Oblivion, it's been a much faster transition. I really like and enjoy the Elder Scrolls series, but I was dismayed that I couldn't like and enjoy it more. I've read a lot of Cog's views on Skyrim and I agree with most of them (His thread titled "A New Gaming Paradigm?" (iirc) was one that I liked a lot).
Skyrim, I think, was a great idea with great intentions but an unfortunately lacking execution.
EDIT: This thread -
http://intpforum.com/showthread.php?t=12160