If he had never done anything other than Father Ted he would have still been fondly remembered. The utter joy of watching him bouncing around to Shaft in that final episode, albeit knowing that was the last full day of his life. The amusement of his frustrations with Father Dougal. He was not an actor but he managed to make an awful character into a likeable hero - almost!
I was very sad when he passed as it seemed, perhaps, that given the right vehicle he would have become a huge TV entertainer.