Some thoughts on your thoughts:

1) That scene in the mail room at the end is chilling. Even though Grubitz laughs with the bloke he manipulates, he still winds up in the mail room.

2) The scene where you see him delivering junk mail, and Dreyman watches from a distance, is so moving. I love the way Dreyman almost speaks to him, realises his words would be futile, and instead goes and writes a book dedicated to him. The final scene where the shopkeeper asks if he'd like it gift-wrapped, and he says "No, this is for me." - I was profoundly moved. Not only by the story, but because as a writer myself, I have written novels dedicated to important people in my life. One doesn't write novels for just anyone, so the importance of what Dreyman did hit me like an emotional ton of bricks.

3) I do think Wiesler mellows throughout the film (the scene in the lift, for instance, where he asks the name of the ball, instead of the boy's father who had muttered subversively about the state). But I take your point about who he is monitoring being the cause of this, and had he monitored someone else, it might not have happened.

Really glad you enjoyed the film. :)