Enough ham for a medieval banquet, in my humble opinion. "I don't like this..." No, neither do we, dear.Velda was such a ham though.
In most of the cases people have mentioned, I'm pretty glad these characters didn't appear any more! In the case of certain evil characters, I'm also quite glad they weren't used a huge amount, since it preserved some of their mystery and menace. I would have liked Lord Fear to have been handled a bit more like that, really. The exception, in my view, is Aesandre, who I would have liked to have seen back in Series 6.
I think it was a great thing that Festus wasn't seen. The imagination of children could have created something far more fiendish than the computer graphics of the time, I think. I suppose also there was always the question of whether Festus might just appear in the current quest, so it helped create some anticipation once the kidsies saw Mrs. G. and heard that wonderful electronic barking roar.