I don't think there's been an in-depth explanation for the changes, and at this point I doubt there will be one. I know EA_Aljo has mentioned multiple times that the developers are aware of the community's desire to have the filters return, but I can't imagine them returning in NHL 25. Maybe in some future game.
I don't have any kind of inside information, so this is just me speculating, but to me everything about the matchmaking changes this year ( loose server selection, no player count matching, no rank/skill based matching ) indicates that the devs had a mandate to reduce the time people were searching for match-ups. And technically they've accomplished that goal. Each individual search is generally pretty quick, at least for my club. The problem is that it now takes multiple search attempts to find a match-up that results in an actual game being played because one team or the other backs out due to ping, player count mismatch, etc. The end result is we're spending at least as much time looking for games as previous years, if not more.