User blog comment:123Action/A Year/@comment-4814726-20131107051411/@comment-5102537-20131108144001

I'm not sure if it had always been the plan to end it the way it was done - though they said it was.

However, I think it's safe to say that quite some things were changed along the way. For example making Arthur king so soon. Uther was supposed to stay much longer on the show according to the staments of some officials, plus the dragon telling Merlin that he was destined to protect Arthur until he is king and that once he is, magic-users will be free and Albion united. As we know, Merlin protected Arthur far beyond his coronation and nothing changed.

When considering this, it's actually unlikely that Arthur would have died in the end. If Uther had remained being king until mid (or the end of) season five, there wouldn't have been time to hasten through the entire Camlann-story, except they had kept Uther in depression and put aside so that Arthur was regent Prince the whole time.

Another thing that was most likely changed was that Morgana was Uther's daughter. There was not only some flirting between Arthur and Morgana in season one but there's also the story around Morgause and Morgana being half-sisters. I would imagine that they were half-sisters through Gorlois at first but that it was changed when they made Uther her father but Morgause and Morgana remained being half-sisters.

Then Morgana turning so ridiculously evil... I can't believe that they had this in mind when considering what she was like in the first two seasons.

Uther's character being completely re-written in season four and five. I think this wasn't planned either because it simply made no sense at all.

Balinor hiding from Uther and being a dragonlord when Hunith told Uther in season one that he was a fair and just king - even though he was the reason why Balinor was on the run. Made no sense either, except she simply said it to address Uther's benevolence in order to get the desired help.

And the entire "it's a story about Arthur and Merlin before the famous Arthurian legend begins" wasn't a subject anymore in season four and five either. All the famous legends were being told within those two seasons, ending with Arthur's death. Excalibur/sword in the stone, Lancelot and Gwen, Mordred, Morgana becoming evil, Arthur being king and marrying Gwen, the Round Table, Arthur dying in the battle at Camlann... the only thing missing was the search for the Holy Grail. That is, if the Cup of Life wasn't the actual Holy Grail here.

Edit: I forgot - I think Mordred's story was changed too. He promised Merlin that he would never forget his attempt to stop him, yet no revenge or grudge was there when he returned as an adult. Arthur suddenly forgetting about who Mordred really was was  also ridiculous since he had saved his life before and knew his name, not to mention that he was a druid.