Cheez, you remain one of my favorite forumites, despite the fact we hate one another's worldviews. Lol.
But this wall o' text is truth. It summarizes the feelings of the core of the fanbase. It explains all the nonsense that this forum has degraded into since release. Well, most of it.
I remember the first time I finished ME2. I got up, got a drink, and started another playthrough. Lol loser me. But that threshold is long past. I completed several playthroughs of ME2 before I moved on. ME3? I may have been biased, but still, it hurt. It just hurt so much. My first playthrough of ME2 I got half my squad killed. No joke. And I loved many of the characters. But the tragedy did not turn me away. I knew that I could do better.
ME3? Tragedy? Yes. But tragedy was expected. Earth and many other worlds had been invaded. Much of the beauty had been destroyed and replaced with a dystopian nightmare. But this did not destroy hope, the will to fight. Up until the ending, there was still hope.. until it was finally gutted for confusion and despair.
The end does not have to be happy. ME2's wasn't. ME1 is debatable.
It does not have to close all opportunities for the future. You saw all the speculation about what could and what would happen in ME3. Much of it was downright crazy, but far from baseless.
The end has to be consistent, sensible, and give a reason to feel accomplished, to know you did good, whatever the end may be. The current ending is none of those things.