Arya's scenes were awesome, real highlight of the episode. Especially the hall of faces. I also thought the face she touched in that hall looked eerily like her mother's. Another highlight of the episode was indeed Alfie Allen's acting.
Dorne's stuff was ridiculously bad to be honest. I'm really surprised it made the cut in a show like this, they usually do a great job, and Dorne is a huge miss for me so far. Casting (except Doran), storytelling, everything is just isn't doing it for me at all.
I'm also not sure about the Loras' birthmark. I mean, Olyvar was his squire, alright, but (in the books, at least) squires sometimes are asked to prepare a bath for their knights, this kind of stuff (Peck, Jaime's squire in AFFC does exactly that). So Olyvar could've spotted Loras' birthmark in some other circumstances, I guess.