HMCS Harry DeWolf in ice (6-8 second exposure)
The August, 2021 issue of US Naval Institute Proceedings has an article, that is the first I have seen to discuss the roles that should be expected of the “Arctic Security Cutters,” the Coast Guard’s planned Medium Icebreakers.
The article is available on line. I am not sure if or for how long it will be accessible to non-members.
The thrust of the article is that these ships should not be limited to deployments in the Arctic. That they have important roles in Antarctica and might also be used for domestic icebreaking, particularly in the Great Lakes during unusually severe winters, or if the Great Lakes icebreaker Mackinaw should suffer a casualty. I have suggested something similar before. It is also likely we will have reasons to operate in the Arctic entering from the Atlantic side.
This would require a homeport on the East Coast, perhaps Newport, Boston, or Kittery, ME. It would mean the ship would have to fit through the locks from the St. Lawrence to the Lakes and between the lakes.
To qualify as a “Medium Icebreaker” in the Coast Guard lexicon, the ships would have to have propulsion motors totaling 20,000 HP or more, meaning it will be more powerful than the Canadian DeWolf class Arctic Offshore Patrol Ships, like the one pictured above.
The author suggests a design evolved from the Wind class Icebreakers. These were very successful ships, but the design is about 80 years old, so we can certainly do better. Even so, the successful use of the Wind class globally shows what can be done with a design smaller than the planned Polar Security Cutters.
That the Coast Guard continues to claim a requirement for a medium icebreaker class rather than simply building more Polar Security Cutters may mean they have recognized a need for a smaller ship, perhaps one that could operate in the Lakes or in shallower water than might be accessible to the PSC.
Questions remain regarding the expectations of the class. How will it be armed, and what sensors will it be equipped with? I would anticipate an outfit similar to that of the Offshore Patrol Cutters, but that is yet to be seen. Should it be capable of operating more than a single helicopter? UASs? USVs? Space and utilities to support containerized systems? Space for a SCIF? I look forward to hearing more about this class.
Chuck Hill's CG Blog 
Proposing a Wind class derivative as the Arctic Security Cutter is not unlike proposing a DC-3 derivative as the USCG’s next fixed-wing platform. Both designs performed well at their time (and well beyond that), but as you said, a lot of development has happened over the past 80 years. It’s probably easier to start from scratch than try to adapt a more or less obsolete design to today’s regulatory regime, shipbuilding practices, operational needs etc.
Chuck, I’m playing catch-up on some of your older posts, your comment: (I’m look forward to hearing more about this class”) Me too. Will it be an “Arctic Security Cutter” or a “Arctic Security MedIum Icebreaker”? Meaning what is its primary mission? Security or Icebreaking. Something like the Canadian DeWolf class Arctic Offshore Patrol Ship but with better icebreaking capiblities and better armed could do both roles. Six of them, three on east coast and three in Alaska. That would free up the OPC planned to be based in Alaska and northern east coast for basing in other locatings, like the western pacific.
The plan is for three Arctic Security Cutters. I get the impression at least one will go to the East Coast, but nothing official. I have not seen the High Latitude Study. it may have some information on that.
The Coast Guard definition of a medium icebreaker has nothing to do with size, it is all about the horsepower, 20,000 to 45,000 HP. They might end up being very large, like Healy or even bigger to make room for research requirements.
That might preclude using the same design as a Great Lakes icebreaker.
Specs seem to be still in flux.
Getting to three ships by putting two new ships on the Atlantic side and leaving Healy on the West Coast would make sense. But ultimately Healy will have to be replaced in about 20 years.