I won't lie, the only reason why I liked Oblivion was for the graphics. It was one of the first "this" generation RPGs using SpeedTree, FaceGen, the Havoc engine and a few other nice quirks. But looking back on it, I've realized that without all the "shiny" features, there was really nothing interesting there. In fact, I would argue that Oblivion was Bethesda's laziest TES game to date. Most of the game's mechanics were outsourced to different companies, very little of it was actually done by Bethesda. Oblivion is possibly the worst of the official series, perhaps on par with Arena.
This has just happened in the last few years (maybe since DF came out), and this may sound odd, but I don't like "fun" games anymore. In other words, I don't like to sit down for 20 minutes and just shoot stuff or jump on platforms with pretty colors and nice sound effects. I like my games to be painful. I love it when the graphics suck, so I can use my imagination, I like it when the controls are difficult to learn. I hate games that feel too polished, I like a few half-broken features here and there. I love imbalance, that there is a chance that I will never ever succeed at winning sometimes.
I would argue that this is one reason a lot of us dislike modern games, because they are simply too "fun", they have zero learning curve, and are usually too balanced. I don't like playing games where I know I can win every time. A lot of the old 80s-90s games (and a few from the early 00s) were not fun, and yet that's exactly what made them fun in a special, gritty kind of way.
The best analogy that I can think of is rock climbing in the back-country vs climbing an artificial climbing wall at a fair. It's the exact same thing, yet why is climbing so much more exciting when it's in the wilderness as opposed to doing it in a civilized location?