Wut
I thought the ending was contrived and stupid.
To explain, here's what I wrote in regards on Yahoo Answers at the time, i regard to the ending:
As far as I'm concerned, the movie contained good strong writing, but with a faulty ending thanks to the surprise twist. On the surface, it seems like Batman made a good sacrifice by telling the Commissioner to blame Harvey's bad deeds on him. But if you scratch beyond the surface, I think it makes little sense, for 4 reasons:
1. I understand they didn't want Gotham City to know that Harvey had done those killings, but do the writers honestly expect me to believe that Batman and Gordon couldn't have come up with a better story than to blame it on Batman? How about blaming it on one of Joker's men or even saying they don't know who did them?
2. Noble noble Batman doesn't want Gotham to lose faith in justice and goodness by finding out that a good man did bad things. Well, that's understandable. But Harvey's dead now, and the people do still have Batman to look up to. The city needs someone living to look up to, more than the memory of a good man. Some people in the city wanted Batman gone, but others loved him. Is it somehow better for them to believe that a good man that is still alive has gone bad than it is to believe that a good man now dead did some bad things? The citizens will now hate and fear Batman; what's the point of the good citizens thinking Batman's a murderer? It's ridiculous, in my opinion.
3. I really believe Gordon never would have agreed to do it, because of his friendship with Batman.
4. Besides his loyalty to Batman, Gordon would be breaking the law by hindering a criminal investigation, covering up, and committing mass fraud. I don't think he would do that. I really don't.