What about some better loot for those who dare? I mean, some new rare equipment (always lore friendly, for (any)god's sake!), so that the game becomes even more rewarding? I mean, ok, Skyrim is already an awesome game, and all the DLCs add (more or less) something new and interesting to the "vanilla" version, but I always missed rare armor and rare weapons variety. Yes, I know, there are the Daedric ones, but to be honest, they aren't that cool. I can say right now that even some mods are really interesting, they are anyway and remain extraneous, unrelated to the story itself, even if they are often a remake of the normal equipment we can find/craft inside the game or relics for past games (Oblivion, Morrowind mainly). I'd really like to see some fresh new loot related to the increased difficulty of the game in Legendary mode.
This is quite difficult to happen. Maybe impossible. But, who knows?