Okay but is Marner good enough to play on McDavid's line? I mean, Zach Kassian is, so I'm pretty sure Marner is, even though he's not better than McDavid. (I can't for the life of me understand how he has to be better than Pettersson to play on the line. And if he is better than Pettersson, and therefore able to play on the line, how can Peterrsson play on the line when he's not better than Marner?)
I truly have no clue what your issue here is. I don't understand, at all, what you are talking about.
What does that even mean "good enough to play on that line?" All kinds of different plays slot into different lines. You've completely lost me here.