That's the general consensus now, with Fiala playing like a star 1st liner, while Dumba is sitting on the sidelines injured. However, Dumba is one of the top 3 Dmen on the team, is still relatively young, also one of the few RHD's(almost all the young d prospects are LH), and is very well liked by players and coaches(is an "A").
It was known that Fiala was talented, but I don't think anyone planned for his production to explode like this. Guerin has to be reassessing things right now.
Really, the play is to get rid of a bunch of smaller pieces like Jost, Greenway, Kulikov(having a good year), forget any thoughts of signing MAF/Middleton, replacing all those guys with ELC's (doable).
Zuccarello is also someone MN might look at moving. He is having a career year, and is Kaprizov's wingman and buddy, but do you keep a 34yo over 25 yo Fiala?