Oblivion is not liked but I enjoyed it. The level up system was a bit of a pain, you had to level up 2 secondary skills and one primary with different main stats in order to maximize your levelups. The mobs would scale with your level and you had to maximize your levelup or end up gimped since not all levelups make you stronger, eg. raising alchemy. If you maxed 2h swords, armor, block and strength early on you would be OP. So you would put the skills you wanted as secondary skills rather then primary since you want to have the max skills with the least levelup. This means your optimal build will have the skills you don't want maxed.

Once you got a handle on the way you level it was nice.

Another thing that I didn't like is that spells used to be OP but then they nerfed spell creation by drastically increasing mana cost for absolutely no reason, single player games should make you OP in end game, it doesn't need to be balanced.