Judging by the posts I've read, most of these people haven't actually played through the ending of the ME3. Seriously, read this PC Gamer article featuring other game writers, and tell me how many of them have actually beaten the game in question. Heck, most of them are too busy shilling their own game in their answer. So much for their vaunted artistic integrity.
In any case, there are two points I'd like to make about artistic integrity.
Artists Make Mistakes
Artists are human beings just like the rest of us. That means that they too can make mistakes, even when it comes to their own art. Their choices are not always the best choices. Sometimes, the artist can go back and fix those mistakes. Or, in the case of George Lucas, make new mistakes.
My favorite movie is Ridley Scott's Blade Runner. But the version I adore is not the same version as the one released in movie theaters. It is significantly changed. In fact, Ridley Scott has continued to tinker with the film. He has been fixing his mistakes.
Most mediums don't really allow the artist to easily fix their work. Plays and theater do, and playwrights have often adapted their works after initial runs. Sometimes movies can when new editions are released to take advantage of new mediums. I've read novels where the writer returns to her work (often the first book published) ten or twenty years later and updates it, editing it better, adding a couple scenes, and generally cleaning up and polishing.
Computer games are a medium where it is easy to make changes, to fix mistakes. None of us would blink an eye at a patch that fixed a mechanical imbalance. Why is fixing a story mistake so far beyond the pale?
There is an old story about Winston Churchill and a socialite:
Churchill: "Madam, would you sleep with me for five million pounds?"Mass Effect 3 had such crass marketing ploys as Day-One DLC and a pop up during the ending urging the player to purchase more DLC. Those sorts of stunts already establish exactly what sort of company Bioware is. And it is not exactly one brimming with artistic integrity.
Socialite: "My goodness, Mr. Churchill... Well, I suppose... we would have to discuss terms, of course... "
Churchill: "Would you sleep with me for five pounds?"
Socialite: "Mr. Churchill, what kind of woman do you think I am?!"
Churchill: "Madam, we've already established that. Now we are haggling about the price”
A company cannot indulge in things like Day-One DLC and expect the audience to take claims of "artistic integrity" seriously. We already know that you're for sale, and we're just haggling about the price.
I regard the ending of Mass Effect 3 as a mistake. Unlike a lot of other artists, the medium Bioware works in offers them the chance to fix that mistake, to improve the work of art. As well, by choosing to indulge in marketing shenanigans, Bioware has already compromised its claims of integrity, and those claims are not likely to be taken seriously by the audience.
From either side, I find the excuse of "artistic integrity" to avoid changes to be very weak. But if Bioware honestly believes that their ending is the best possible ending, that on reflection it was not a mistake, then they should stand by that ending. That choice has consequences, as the audience is free to disagree, and re-evaluate the quality and skill of the artist and the work.
Note: The comment thread may contain spoilers for Mass Effect 3.