If you read the opinion piece, you'll know that I am really not a fan of dailies. I do a few, though, purely the jewelcrafting ones, as long as it's not the Elemental Goo quest. I can't be bothered with that one, so I stick to the stardust one and the making three of a certain gem ones. So those quests are good because they're easy. They give you rewards, which, if you want to craft gems, you kind of have to get. But I don't really enjoy them!
I figure a good daily quest might be one that slots in neatly with something you already do. I wrote a piece a while back daydreaming about MoP PvP, and maybe I should add dailies to that -- dailies where you go into a Battleground and honorably kill a troll or a dwarf. You get a few extra honor points for that particular quest, and you're done. It was something you enjoy anyway, you just had to make sure you were around for the killing of a certain race of the opposite faction. For me, a good daily would have to be something along those lines, since longer ones, even ones with a fantastic story, would get old with repetition.
But maybe you think that dailies should be harder than that and should send you out of your way or make you do something you don't really want to do. Or maybe they should have a story behind them and take you out into the world. Or should it be something else altogether?