User blog comment:Aithusa07/List of Plotholes from Merlin/@comment-32920116-20170822062432/@comment-80.194.173.91-20180131164402

This is probably so old now people have stopped reading these things, but i'm writing fanfiction and am interested in seeing what things the show didn't clear up so that when the times came, i would be able to explain it in my version. Anyhoo, I TOTALLY agree with you. The whole point of this particular story of Merlin is to show that there is not going to be a happy ending.

Merlin starts off as an optimistic, wide eyed spring chicken with a naive opinion of the world. As he gets closer to the people around him and as he settles into his destiny, he is pulled every which way. Listen to me, don't do this, don't trust him ,let her die. At first he would not listen and go by his heart and do the opposite. BUT as years go on he becomes paranoid and darker with his view of everyone and listens so much to what people say is destiny, and THAT is his downfall. The dragon once said that 'his determination to see goodness in people would be his undoing' However in the end, it was the opposite.

Merlin learns the trick is to listen to destiny when he first looks into the crystals in the 'the crystla cave' and learns by the end that his actions brought all he saw to reality. THAT was his clue.

Merlin was told not to trust Morgana (while she was still good), he wanted to help her, but listened to the wrong people and she didn't get help, thus changing her into the hateful insane witch she became. Merlin was told nearly from day 1 NOT to trust Mordred (whilst still an innocent little boy), he didn't listen and saved him, only to listen later on and it kept them apart to the point Mordred could have seen the trust in Melrin enough to not join Morgana when feeling betrayed.

And the ultimate tragedy, not letting magic into Camelot when he felt the more important thing was Arthur's opinion of it over Mordred's life. Thus being his punishment, giving him more paranoia than ever about Mordred, a vicious circle.

This is going on a bit now. But in the end. Destiny was a git and made a poor once happy boy into a shadow of himself, he lost most of his friends and a chance to be free. The end.

The obvious plothole about Killgharrah not taking them both to the lake at the end was probably just Merlin's last desperate call. He might have thought that after the dragon's and his last meeting, that the dargon had already died.... i'm guessing.