RPGs need a balance of lore and mechanics to be good, the balance should be slightly tipped to lore though. MMOs in my opinion need more mechanics than lore as most people will probably focus on mechanics when involved with other players. For single player RPGs though I would really like a story line that makes me feel as if I am keeping up with my favorite TV series, trying to figure out what will happen next and hopefully being surprised when it happens. I agree that the main story lines of Oblivion and Skyrim were a bit short and slightly less interesting than some of the side stories.