Re: Arthur, it struck me during rewatch that they're quite clever in how they introduce Arthur at his worst in the pilot and then bit by bit show there's more to him - 1.2., Valiant, shows he has a keen sense of duty (and is good with swords, but that's not necessarily a positive quality by itself) along with the arrogance, 1.03. has him argue that if Gwen (who at this point isn't anyone other than Morgana's maid to him) tried to save her father via magic, she should be judged by intention, not as if she wanted to kill someone, i.e. he displays a sense of ethics differing from Uther's, the same episode also has him come up with an excuse for Merlin when the later tries to confess being a sorceror to Uther in order to save Gwen (and Uther would definitely have had Merlin executed otherwise), and 1.04. has him defy Uther and risk all to save Merlin's life after Merlin drank poison to save Arthur's. While at that point they've started to bond, I'd argue this is still more done because Arthur actually does believe in noblesse oblige (as opposed to Uther, who claims to but doesn't follow up) and loyalty to those who are loyal to you than out of affection. Now, along with this he also continues to display arrogance, rudeness and some obliviousness in all these early episodes, but as opposed to pretty much everyone else who gets introduced at their best, with their dark sides and flaws revealed later, Arthur gets the reverse. (Usually something they do with morally ambigous characters or antagonists, not secondary protagonists and heroes.) It's very effective.