I do hate "because the plot said so" conflict (doesn't everyone?). I remember Katie McGrath moaning on the commentaries how all Morgana needed was a frank conversation with either Merlin or Gaius to keep her from turning evil (though I suspect she's having much more fun now) and she was quite right about it.
Now I can't for the life of me understand why Gaius didn't whip up the pendant the moment he noticed it and shoved it into Arthurs face, shouting "Morgana!". I mean, it's not like Arthur doesn't know that Morgana is A) a sorceress B) bent on destroying Camelot, and C) hating on Uther in particular. In fact, I'd say that there's plenty of material with Morgana's character (childhood friend, half sister, driven half-mad with power) to keep Arthur conflicted about magic without dragging ridiculously contrived conflict in this.
Having got that off my chest:
The knights! they got almost nothing to do this episode but Percival's faces were awesome!
Evil!Uncle gallops in the night in a black cloak on a black horse! He is evil! Though he is starting to acquire some interest... I dare say he's in all this to benefit himself, and isn't particularly loyal to anyone, really.
Gwen's purple gown looks much better than that misshapen blue one. And she looked especially lovely this episode. I was waiting for Arthur and her to share a bit of a tender moment in Uther's chambers and for the dying king to notice and warn Arthur off (see? I can do overwrought drama/conflict! as long as it has logic!).
I appreciated the assassin having an actual plan instead of just whacking the prince in front of the whole court... and that said plan involved narcotics! See how logical and in-character that is, considering Arthur is Camelot's best warrior and trying to kill him with a sword could prove quite the challenge otherwise? Also, wobbly pretty boy, I won't lie.
UTHER UTHER UTHER. Tony Head, being a BAMF. I LOVE YOU SON. I'M PROUD. What a great way for Uther to go, protecting Arthur with his life. The night vigil, so beautifully filmed. YES.
OMG ARTHUR IS KING, finally!