User blog comment:MerlinUSA/Merlin -- The Big Picture/@comment-5764349-20130116222339/@comment-5995315-20130117032932

Well now we're speculating about the future, but the finale led me to the conclusion that Albion was safe from the worst danger it had ever faced. Arthur said he was fighting for the future peoples of  a "united kingdoms," and here we all are today. Therefore, Arthur must have succeeded.

The Disir episode was a test of Arthur's greatness. He refused to put his people in danger by accepting whatever arbitrary magic the Triple-Headed Goddess wished to impose. He could also not in good conscience bow down before  a religion he did not believe in, even if it killed him. That was a responsible decision, but it doomed him and he feared as much. But he acted out of duty as king.

If Gwen knew her husband had been killed by magic and the only good magician had gone AWOL, she would be within her rights to ban it. However, the finale shows her keen intuition in being the only person ever to figure Merlin out, and her reaction to Gaius was very positive. I'll go with the dragon: If it was Arthur's destiny to restore magic, then he must have, through Gwen.

As to Katie, she knows her character better than most. If the question is whether Katie is lying or telling the truth, logic dictates you assume the person is telling the truth until you have evidence they're lying.