why not 11-7

Yeah TB isn't bringing Schmidt and Thompson up to go 11-7 regularly or sit them. They're much more likely to be playing them 20 minutes a night in Syracuse TB will make a player stay longer rather than sitting up here especially being waivers exempt.
Cf had Stamkos positioning wrong he plays the left on PP or when playing with Kucherov and Point when not he's C/RW. Lines something like
38-21-86
79-71-91
84-20-23

Seth Jones
Connor Murphy
Nikita Zaitsev
Ian Mitchell
Caleb Jones (plays both sides)

And Alex Regula is knocking on the door for a roster spot. There's no room on the right side unless someone goes. If Murphy gets traded then there's a possibility that the Hawks consider exploring a trade for Myers but for only a 6th there might be better options or better dump returns.

Schmidt needs development minutes so AHL 1st pair would be good for him

I'm not a fan of this Myers trade either, but the Hawks depth at RD isn't that great. Jones is going to be here, Zaitsev could be buried in the minors, Mitchell may not be qualified, and Regula won't be a regular, maybe an injury call up at best. As for Murphy, he's got the most trade value. Personally I would like to see him moved at the draft so Davidson can get another high pick. If Murphy is moved then Davidson can take on a RD cap dump (Tyler Meyers/Tyson Barrie type) and pick up another pick along with the player.