A GM brought in around the 4 nations break could have already influenced scouting for the draft, identified roster decisions they want to make that might be difficult while there were still games to tweak and assess (e.g. whether to buy out Samuelsson, whether to trade/extend Byram, etc), and possibly already planted some seeds at the trade deadline with other GMs for roster building trades this summer.
Maybe "largely a lost offseason" is an exaggeration, but it would be way better to have the last 1/3 of a season with a new group vs a lame duck. I'm pretty sure Adams won't get fired anyway though, so it's moot.