I think that people (fans) need to let go of their traditional ideas about how a team is constructed. The idea of #1,2,3 and 4 lines ordered by scoring is not something that teams actually discuss any more. If teams could spread their talent equally over 4 lines and be competitive the salary cap makes this impossible. It is more about balancing the top 9 and having an effective 4th line that they can roll out regularly without being a liability.
Moving forward I see this team with 3 natural centers in the top 9 (Kotkaniemi, Poehling and Danault) This leaves 6 winger spots in the top 9 (Gallagher, Caufield, Suzuki, Domi, and two of Tatar/Drouin /Ylonen). That has the potential to be a lethal top 9 with 3 strong two way centers and a ton of skill on the wings.
The only way that I see Domi hanging on to his role as a center is if we lose Danault in the expansion draft. Even if we lose Danault there will be a question of whether Suzuki or Domi should fill that void.
I absolutely love Domi's skill and drive but he is a liability defensively at times as he has a wingers mentality of staying high in the d-zone and leading the rush on the counter attack. If Domi is going to remain at center then he will have to receive softer/insulated minutes while Kotkaniemi and Poehling take the more difficult assignments. In a perfect world you don't want to have to protect any of your top 3 centers and as of right now we have exactly the type of centers that should be able to handle anything with Domi moving to the wing.
It is an unsupported conclusion to say that Domi's production increased because he moved to center. It may very well be completely coincidental as there are multiple reasons as to why his production increased. He was a winger as a rookie and had an outstanding season, clearly there were factors outside of his position that contributed to his reduced production.
I am not preaching to you as I know that you understand the way the NHL is changing The first paragraph was simply an axiom from which I could build a case for other readers.