I was delighted to have John Hurt in it because really what can't be improved by having Aragorn/Caligula/Quentin Crisp/Hazel the rabbit/Malcolm Scrawdyke in it?... the man can play anybody.
But I have to agree with the above comment that it would've been preferrable if McGann had been the "War Doctor" since his marvellous turn as the The Doctor never go a fair shake (Visually anyway). And yes despite my overall enjoyment of the special, we never actually saw the "War Doctor" do any warring which was odd.