I totally agree with your points! Such a good build up and then the end was a big 'meh' for me. Im not sure if this is correct but apparently they did reshoots for the ending, something about how it was suppose to be a female "god" like character but I'm not 100% sure.

I really enjoyed the romantic part of it more actually, Damon and Blunt had really great chemistry! And that dancing!!! love her!!!