Now that I am at the cabin and can finally type on a real keyboard instead of the phone ... I want to give my thoughts in depth.
The Dumoulin signing in a vacuum is fine. He replaces Soucy, and he will be better simply because he was given 1st pair minutes in Pittsburgh as opposed to 2nd or even 3rd pair minutes he gets on the Kraken.
There is a way to go still before the season starts, but I am curious to see what else Francis does. If he truly goes into next season with just a Dumoulin and Soucy swap, we will likely take a step back because we still need to make up for the loss of Donato, Sprong and Geekie's production. Kartye is a good start there but the playoffs were too small of a sample size to know this for sure and if he can play an entire NHL season at a similar level as the playoffs.
The D still would be pretty solid, assuming we re-sign both Borgen and Dunn:
Dunn-Larsson
Schultz-Oleksiak
Dumo-Borgen
Megna/Evans
But the forward core needs more skill:
McCann-Beniers-Eberle
Schwartz-Wennberg-Burakovsky
Tolvanen-Gourde-Bjorkstrand
Tanev-?-Kartye
We will find out in the next few months, or hopefully sooner, but we barely made the playoffs last season, and our good run was aided by Gru getting real hot. I don't know if we catch lightning in a bottle again with this roster.