Given the fact that he didn't want to be Batman; it makes it hard to imagine what it would have been like if he did in fact accept. Now imagining that he was totally up for it, and accepted is different. I see him just doing a great job, but ultimately mediocre comparing it with his Joker performance. He created a NEW Trendy Halloween costume to wear, a new iconic movie villain, and IMO gained more NEW fans for Joker.
It is always sad to see a positive person leave this Earth. Only adding to the sadness, when they still had so much potential, so much to still give.
His Legacy will Live On