The case for trading the 'core' (to me I'd trade/get the best I can for Matthews and Marner)
-If you think Culture is a problem, 2 or 3 of the big 4 need to go. You aren't going to deal no-one or just Nylander, and bring a guy in who will take over the room from the other guys. You need to flush that out, again, if you think culture in the room is an issue.
-These guys aren't worth nothing. If you trade Matthews and Marner, you are getting a LOT in return. Maybe you get less talent back, but if that could also mean more cap space. You can get slightly less talent back for them, but get some picks with that AND have more cap space to re-sign the guys you want to or go out and get some one else.
-Finally, if they lose this series in 4 or 5...and you do NOT make any moves, just how much can we enjoy this team. They could compete for the presidents trophy next year but its getting to the point where it is almost not even enjoyable. With a new core, we get to watch/talk about something new. With this same core, NOTHING will matter except/until the middle of April of next year.