i think JT Miller should play over Carcillo and Dorsett.
IMHO Miller has a future with this team going forward...this experience could be good for him.
He doesn't look ready. It's the playoffs. You don't worry about player development, you worry about winning. There is no way playing Miller over Carcillo/Dorsett gives us a better shot at the win.
I like Miller and think he makes the team next year, but if Kreider is ready to go, Miller shouldn't play. He would bring little to the fourth line.