Fine.
The reason you trade Nuge is because he's the only expendable player who has a chance at getting a top 4 RHD puck mover. Something this team has desperately needed for years. In a cap world it also doesn't make sense to pay your 3rd line C $6M. We keep trying to force this ideal of 3 scoring lines but we barely have enough wingers to ice two.
RNH-McDavid-Puljujarvi
Lucic-Draisaitl-Khaira/Slepyshev
or
RNH-McDavid-Caggiula
Lucic-Draisaitl-Puljujarvi
There you go. 2 lines. 3 centres. Don't tell me that this lineup looks better with Maroon in place of RNH. It doesn't. And if you don't like Nuge on the wing, here you go:
Khaira-McDavid-Draisaitl
Lucic-RNH-Puljujarvi
Again, put Maroon in, it doesn't look better. I personally prefer the first setup, but both work.
I also truly believe that Khaira is our next Maroon. The exception, however, is that Khaira is 23 years old, and has been impressive away from McDavid, and can grow into a consistent 20 goal guy, whereas Maroon has a track record indicating that he is purely a product of McDavid. And Khaira comes cheaper, and can play centre if need be. And Khaira (due to age) is a slightly better skater.
Also, I don't believe the RHD is as essential as you do. Between a group of Nurse, Larsson, and Sekera, I think our top 3 D positions are solid for now and the future. Trading Nuge for a guy who isn't needed in the top 3 is foolish. What we need on D is stability and depth. So either Klefbom plays well next season, or he goes. Davidson and Russell should be a fine third pairing. Need to move Benning. But our defensive needs aren't so big that we need to move our leading goalscorer.
Edit: Plus, I'm willing to bet that in 2 years, at least one of Yamamoto and Benson is an NHLer.