I'm still reading Bokurano, finished only half of it, it's kinda so depressing it made me sick at some point (not emotionally, but physically).
But unfortunately I've already spoiled myself with the ending some time ago .__.
What I just wanted to say is... don't know if the end's good or not yet, but if the "game" continues, then at some point there will be no one on earth left to protect, because new pilots will substitute the dead ones, and after some time (even if it's hundreds of years), there will be no one left to protect, so what's the point.