No feedback? This is a criminal offense! Must - redress - injustice!
It is a personal milestone, yes, but can Clark/Kal be trusted at this point in his life? Lois may understand intellectually why he's done what he's done, but that's a long way from trusting, respecting, and loving him. And what has Bruce been doing lately? I understand that he's letting Lois do the information gathering, but Clark killed Jason Todd. How is he going to learn to trust the Kryptonian? The only way to prove to Clark that he's trusted is to remove the collar - and that's a one-way street. Clark would never let it back on him.
Let's say Bruce does it. How long does Bruce think Lex Luthor will survive? Another kill for our "dear assassin" (what a terrifying turn of phrase), and it would be tantamount to slitting the man's throat himself.
That can't be the only green K Lex has. If Clark loses the collar and avoids Lex, how many others might die at his hands? He may know that his lifestyle is evil, but he knows nothing else. Once an assassin -
You've woven a deeply dark tale, DC. I want to know what happens next! I want to know if Kal ever sees the light, or if he takes out Lex with his final act of violence. And don't worry about the lack of written feedback. I suspect we'll all remember this tale for a long time.