I know I'm gonna sound like a broken record, but my number 1 thing on the list is a complete overhaul of how goalies are handled in the game, from the day to day decisions to pick who starts in net, to how the AI evaluates goalies for trades, drafts, signings, etc. As much as I love this game, the goaltending "systems" are far from working optimally and have not for at least the past 3 iterations of the game. I think it's time to give it some love.
My pipedream is and always will be to have full historical teams/leagues/minors/players. I do, however, understand it's a massive undertaking and it probably would take several years to get done due to how fragmented hockey history is. There is always a bit more added to the historical part every year though, so one can always dream it's going to come to fruition one day
