The Chicago Blackhawks have finished their coaching search and have landed on former Detroit bench boss Jeff Blashill. Blashill was let go by the Red Wings after the 2021-22 season but is returning to head coaching duties with the Blackhawks being not very far off from where the Red Wings of the late 2010s found themselves.
If there is one way to differentiate Blashill from previous 'Hawks coach Luke Richardson, it's what their teams do when leading or trailing games. From HockeyViz, we can see that in Richardson's last full season with Chicago, his teams went into an offensive shell (bottom-left) when they were up or down goals, but they were basically giving up the same quality of shots against:

In other words, the Blackhawks would abandon their offence, nominally to improve defensively, but didn't actually improve their defensive play. (While that graph is just from the 2023-24 season, it is very similar to Richardson's partial 2024-25 season.)
Conversely, here is Blashill's last full season with Detroit. While his teams do go into a shell with the lead, they improve defensively, and even improve offensively sometimes:

If nothing else, this alone is good news for fantasy hockey. If the Blackhawks ever actually manage a lead in a game, they are often going to keep their foot on the pedal with Blashill behind the bench. That hopefully leads to some more production they otherwise wouldn't have.
Outside of that, Blashill can only do so much with this roster. The defence is young and has very high upside, but needs years to realize its potential. Connor Bedard is around, which is great, and Frank Nazar took big steps in the second half, but after that they're relying on marginal veterans or lottery-ticket forwards. Blashill isn't shy to use young forwards a lot – Dylan Larkin averaged 21:33 per game from 2018-2020 – so Bedard may be in line for another increase in ice time, which helps his fantasy value. Maybe Nazar takes another a big step forward and provides secondary scoring this team hasn't had in the Bedard era.
But Bedard and Nazar, and the young defence group, need help. Legitimate help. Ryan Donato and Teuvo Teravainen had fine season but the fact that Ryan Donato and Teuvo Teravainen were the team's number-2 and number-3 forwards behind Bedard should illustrate the point that this roster needs more help than a new coach. Blashill should be fine, and may be helpful on the margins in terms of ice time and pushing the pace with a lead, but for this team to have fantasy relevance outside of 2-3 players, a lot more needs to change than a different guy holding the whiteboard.