Kasurami said:
'It's art!' is the most pathetic defence for anything ever. So what? Just because it's 'art' doesn't mean it's not open to criticism or challenge or God forbid revision. I guess Charles Dickens rewriting the ending to Great Expectations threw literature back a decade too? Jesus Christ. The word 'art' is the most transparent shield imaginable.
Few things are examined as closely, or criticised as thoroughly as art. Art isn't or shouldn't be a defense to criticism or inspection. If anything, it's an invitation. If people use it as a shield, they're wrong.
However, art is dictated by the authorial mandate of its creator(s). Admirers of a piece of art should not possess editorial power over it. The problem with this whole ME3 debacle is that instead of people saying more reasonable things such as "We though the ending was bad, because of this or that.", they are saying things like "Jesus Christ, this ending is so horrendous, we want you to change it, and you should because you owe us because this is a product, we're the customer, and we don't like it."
This is also why it's disappointing to see Bioware potentially cave in. What's happening is that if they decide to change the ending, they are not doing so based on a discussion with the fans in which the fans demand nothing. Instead, they're changing it because of an incredibly vocal part of the community that outright
demands changes to the ending.