I enjoyed watching this show, but it could be tough at times. Let's imagine briefly what the writer's room must've sounded like:
- Let's tell the Arturian legend, but let's begin with Uther still alive. He's also sort of a tyrant and a hardass, but not completely unsympathetic. That'll make for a lot of fascinating questions of political theory!
- Oh, and Uther hates magic because he tried to use it once and shit went real bad so now he executes anyone caught practicing it. That's going to make things really uncomfortable for someone like Merlin and will let us make all sorts of half-assed metaphors for homosexuality, religious fundamentalism, and the like! To really drive that home, let's make all the magic users "born" with magic, so they can't help it. They're just being who they are!
- Let's also make Merlin young, so this is a coming of age and hero's journey sort of thing for him, but he has to hide his greatest talent because of #2. We'll also make him Arthur's servant, because why not. Also, let's make Guinevere a servant too! And she'll just go by "Gwen." Then we can also tell a story about classism when Arthur falls in love with her! Let's also put together a half-baked love triangle between Arthur, Merlin, and Gwen, then abandon it immediately.
- Let's also make Arthur young, also very fratty and brotastic so we can show a lot of character development as he slowly grows from being Fratty McFratterson to an actual decent guy. Nevermind that both the characters and the viewers will be left wondering "The once and future king? THIS guy?"
- You know what? There's too much "gritty" fantasy on TV, what with the Game of Thrones and all. Let's make it family-friendly! This may hurt us when we have to deal with torture, murder, and battle sequences, but think of the ratings!
This sounds like the setup for both a great show and a colossal disaster. In this case, it was yes and also yes. I liked this show, which delivered a lot of solid episodes, decent acting, and plotlines, but it could have been something truly special. Instead, it ended up overusing a lot of tropes over and over again because the writers straightjacketed themselves with the premise (and likely with the beeb's production budgets). Some of these oft-reused stories are:
- There's a tournament, and someone is using magic to cheat and/or get an opportunity to kill Arthur or Uther! (This happens almost once a series)
- Some mythical creature is pretending to be human and has used magic to bewitch Arthur or Uther into loving them or falling in love with some minion. (Not only did this happen more than once per series in the early going, it was a two-parter!)
- Arthur and his knights encounter some situation that can only be solved with Merlin's magic, but he can't use it or Arthur will know his secret! Thankfully, Arthur will somehow be knocked unconscious during an action sequence, giving Merlin his opportunity!
- There's a spy in Camelot who's feeding information to Arthur or Uther's enemies. This was the most frustrating, because it was the main source of dramatic conflict for each series as everyone attempted to find out who the spy was and Merlin or his mentor Gaius would inevitably be accused.
- Merlin witnesses some knight/noble doing something terrible, like magic or treason or what-have-you, and can't do anything about it. Why? Because he's "just a servant" and no one will believe him over said knight/noble. Nevermind that, of course, Merlin is always eventually proven right and saves everyone's asses every episode. You think it would be a guy some cred, but nope! Titles are everything.
This recycling made binge-watching it particularly annoying at certain points. Especially in the first two series of the show, before it actually unleashes its master-plot. As most BBC shows go, it's finding its footing in the first few series before it really delivers the goods. Morgana, becoming the villain we've all been waiting for, cranks up Series 3 and becomes a real threat going forward that really ties the room together. The show begins to recycle less and less after that, except with the ridiculous spy subplots. Way too much of the stories also count on Arthur's overall obliviousness, which undercut the whole idea that this guy is some miraculous "once and future king" that Merlin must save from himself at all costs.
The actors do surprisingly well with the often problematic material. I'd particularly single out Anthony Head, who turns Uther into so much of a believable anti-villain that io9 wrote this very persuasive argument that he wasn't such a bad king at all. Most of that I credit Head with as his portrayal made his villainy seem rooted in pragmatism and caution more than sadism. Also, there's John Hurt as the dragon. The dragon alone kept me watching the very trying first series. There's just something natural about hearing John Hurt's voice come out of a dragon. He is exactly how I would expect a dragon to sound if it spoke english. I'd be remiss if I didn't point out Katie McGrath, though. While she isn't always given the best plots and is basically turned into evil incarnate by the end, she sells it with every fiber of her being. Sometimes it's scenery chewing, but in the classic way that all genre fiction needs deep down. She's a relentless villain who is often much smarter than the heroes, though one wonders where she gets her inexhaustible supplies of gullible mercenaries. Her motivations for turning on her former family at Camelot are also understandable, if a bit abrupt and a bit extreme.
In the end I would recommend skipping the first series. You're not missing much and will be able to get the context.