A few thoughts:
Yamamoto
Definitely agree with
@780il, Yamamoto and Draisaitl would be great together. Yamamoto has offensive smarts, which is one thing most of Drai's wingers lack. And you can't just look at his weight and say that he's too small. You can look at Myers, who is 6'8 and 230lbs, and is really soft. Unlike Gaudreau, Yamamoto plays with grit and tenacity. I think a more skilled Gallagher is a better comparison. Yamamoto is great defensively and battles hard. He even threw a few nice hits in the preseason so far.
Powerplay
Unlike many posters here, I actually don't mind the 5 lefties on the PP. What I can't stand though is playing McDavid on the right. They need to follow the Jets, and play McDavid in Wheeler's role, with Drai in the middle for those quick one-timers. Lucic as the net-front presence is ok, and RNH can go on the right-half wall.
----- Lucic -----
McD - Drai - RNH
----- D-Man -----
For the 2nd unit, they can do the opposite, and load up on righties:
----- Rattie -----
Pulju - Yams - Strome
----- D-Man -----
The main idea for this is that there are two options for one-timers. There is the player in the middle to get the quick shot off (Draisaitl and Yamamoto) and two on the opposite half-walls (Puljujarvi and RNH), with McDavid and Strome coaching it.
Lines
As much as I believe that Puljujarvi has earned a shot in the top-6, it would be very nice to have 3 scoring lines. I believe Puljujarvi has the capability to lead his line, especially playing softer minutes behind McDavid and Draisaitl. I also think he is better utilized as the "main guy" on his line, as opposed to being the finisher.
RNH - McDavid - Rattie
Lucic - Draisaitl - Yamamoto
Khaira - Strome - Puljujarvi
Rieder - Brodziak - Chiasson
For the defense, I think Bouchard gets the 9 games, since Bear can be called up at any time during the season. Russell should be a solid partner for him, especially playing the left side.
Klefbom - Larsson
Nurse - Benning
Russell - Bouchard