I like the team, hopefully Nico doesn't risk something by attending. Good attitude though!
On D, I'm not very sold on both Siegenthaler and Mueller. All I've watched from them, they were the weak links in their teams defensively, nervously struggling for 60mins. Then again, the competition was the worlds best and I don't know how Loeffel would look in the NHL.. :/
But I hope the main responsibilities go to Diaz, Alatalo, Fora, Moser.
Only a few teams at the WC have rosters comparable to NHL teams though. For every team like Russia and the US you have teams like Great Britain and Denmark. Also the bigger ice surface should take the physical edge of the defensive game a bit and give our Dmen more time and space to make the right breakout play. I think Müller has shown in 2018 that he can be a good player on that level, even though this team had Josi on the roster who took a lot of key responsibilities back then. As for Siegentalhaler if have seen a few games of his this season mainly for New Jersey. In some he looked pretty bad, mainly under pressure, in some he looked fairly solid. Will be interesting to see if he can hold his own in this tournament. If he can't there is always the possiblity, as you said, to give the key minutes to the proven NLA players.
It is however a bit concerning to see our key players on defense getting older. With no top 4 Dmen in the NHL except Josi who turned 30 this year hopefully some young guys like Moser or the junior player Bichsel will make the jump to across the pond in the next few years...