The Dallas Stars fired coach Peter DeBoer after another exit in the Western Conference Final but a lot of the coaching options dried up fast. Just after free agency opened on Tuesday, the Stars announced that they had hired Glen Gulutzan to be their next head coach.
For fantasy, it's hard to imagine Gulutzan having much of a positive impact relative to where the Stars already were. Dallas has finished inside the top-5 teams by goals per 60 minutes both at 5-on-5 and overall in each of the last two seasons. Gulutzan hasn't been a head coach in the NHL in seven years, so how much he's changed his approach to what he'd instill in a team is very much up in the air, but HockeyViz has Gulutzan's Calgary Flames teams going into a shell whenever they had the lead:

That is in contrast to what DeBoer did with the Stars as they would often keep their foot on the gas with a one-goal lead. If anything, it could lead to more shot volume for goaltender Jake Oettinger, which is both a good and bad thing for fantasy.
It is also notable that Gulutzan spent multiple seasons as an assistant with the Oilers, and the Oilers were a team that played heavily off the rush. The Stars played the same way under DeBoer, so it's unlikely a whole lot changes under a new coaching regime. The only change might be to rates of ice time, but we won't know that for sure until the games start up again.
Overall, this change is made with nothing but the postseason in mind. It is Stanley Cup or bust for the Stars, but for fantasy hockey, it seems largely status quo despite the coaching staff overhaul. The bigger change will be whatever has already been done, and will continue to be done, to the roster.