Recently: 'Fable 3'. They threw away almost every good part of an RPG (inventory, character customisation, a story line that made sense) so they could focus on playing dressups, and have 'human interactions' that mainly involved burping at people. For a supposedly 'adult' game it's probably the most chidish thing I've ever played.
And I'll also add my vote for 'Arcania: Gotic 4'.
KOTOR 2 was also pretty awful, especially when they forgot to give it an ending. Which was a shame, because the original KOTOR was awesome.
