Saying out loud "Oblivion DOES ****" is hardly tame. It is that which offends me, and mods add to a game. No game can be good with mods unless its base is good.
Wrong. Do you like cake? Yes?
Try mixing flour, sugar, and raw eggs in a bowl and eating it. Does that taste good? No?
Does that mean something is wrong with the ingredients? No, it means that you didn't use them properly.
Now instead try treating your ingredients properly, and making it into a delicious cake.
Now add dill pickles to the cake. Does that still taste good? No? Does that mean something was wrong with the cake? No, it means that you added something to your cake that ruined what could have been good about it.
Oblivion has some fine ingredients - for example the combat, magic, and stealth systems which are all greatly improved over Morrowind. But there are so many blatant imbalances and shoddy implementations that it spoils the potential of each.
Oblivion also has a staggering world layout and beautiful visuals and hundreds of well-crafted caves. But the insane decision to implement severe level scaling to monsters and chests means that every cave or ruins you enter will have content like a bland puree.
Not only do some mods ADD to a game, but the more complete mods TAKE AWAY the shoddy decision-making by the developers and replace it with something better.