The old wizard dying makes no sense to me.
What was the point of that?
"Here, take this dagger and stab me with it. You can't harm me".
*Stabs with knife*
*Dies*
What purpose did it serve? In the end he was still dead since even when the apprentice threw his ash in the water, he came back only to be "destroyed" a couple of scenes later.
If the point was to allow the apprentice to become a wizard, he simply could have given the apprentice the amulet and send him to go slay the dragon. In that way he could remain at home and be available to the apprentice to teach him later on or whatever.
If the point was to show others that he was a real wizard, then that was a failure since he just died in front of them, and nobody other than the apprentice saw his momentary resurrection near the end of the film.
It seems very unnecessary and stupid to me.