It is kind of hard to think of how to handle the reveal when it comes to Arthur. It would have to be some kind of gradual process, in conjunction with separating himself from Uther's POV. I would love to think that it's happening now, given the way Arthur clearly recognizes that odd things are happening and the way Merlin protests earnestly that he is involved with the fights. Arthur might be in denial, but there's no way he should be surprised at this point.

I am all for Uther crying as much as possible!