The entire series is a power fantasy. Shepard is always told he can't do things. You can't chase Saren. You can't kill Sovereign. You can't jump through the Omega 4 Relay and not get totally boned. Shep does impossible shit all the time, why is it suddenly so important to have it turn out... the way it does?
It's also totally a potshot. You know what sentiment I saw repeatedly in this thread? The desire to reject the Star Kid's crap, and also I saw a lot of posts about how people were so put off by the options he gives you that they just tried to shoot him. Now, if you reject him, and even if you try and shoot him, Shepard dies, all of Shepard's friends die, all of their families die, everybody you've met throughout the series dies, etc.
The only part that really bothers me is the Galaxy at War score. It's meaningless padding and they might as well have just not had it. There's basically two competing ideas in Mass Effect 3: the plot device of the Crucible, and the theme of uniting the galaxy to fight, and I think they end up clashing in a huge way at the end. All of that work you did uniting everybody? Doesn't matter, rendered completely moot by the Crucible. It actually kind of gives ME3 the feeling of Shep just kind of buggering about until the Crucible is ready to be fired, really.