It's rather late, but I wanted to post a quick reaction post for my immediate thoughts.
First, the ''Cup of Life'? That's totally going to be Merlin's version of the Grail, isn't it? :)
Ooh, Merlin being all in the face of the Slash Dragon. He's never coming to visit again? I reckon that totally means the Slash Dragon is going to go to plan B - in other words, suddenly Morgana will be hearing a little voice and the Dragon is going to groom her with evil magics to lead Arthur into a new magical kingdon. Which proably means the Slash Dragon is going to become the Het Dragon and persuade Morgana to seduce Arthur now. Which is a nice way of presenting that bit of plot (if they go with that bit of the legend, since Mordred is already around, and doesn't need to be Arthur's son)
Magical battle! Yay! Does this mean that Merlin's used evil magics? It's hardly the first time he's killed an evil sorceror though, so I'm going to hope not. Lets hope the Old Religion doesn't get sniffy about Merlin killing their priestess too. Although she did say the balance wouldn't care, it doesn't mean to say that good old earthly politics won't come into it.
Oh yes, and the Guardian Angel idea that Uthor put into Arthur's mind? It's a bit lame, but I totally see that they might use this to get Arthur and Gwen together. I will flail like a flaily thing though, particularly if they labour the point for a few eps - in which Merlin saves Arthur, and Arthur believes it's all to do with Gwen being his personal rabbit's foot. And then, of course, Arthur marries Gwen, and Uthor will die, and then Merlin will be like - it was all me! And Arthur will facepalm. And be stuck married to a woman he shacked up with under false pretences. No wonder she runs off with Lancelot, after all that.
God, I might write even this, after Christmas... :)
PS: Oh yes. And there was Bradley's chest. We are now even on the chest front - and I still prefer Colin Morgan. *grins like a mad, slightly ashamed thing*