I recently started a Manager Career in MLS and while the league is enjoyable, several important features that make MLS unique are still missing compared to real life.
MLS All-Star Game
The MLS All-Stars team is fully available and playable in Kick-Off mode, but there is no MLS All-Star Game at all in Manager Career Mode. It would be a fantastic mid-season spectacle event that would boost team morale, give more visibility to the league, and add fun variety.
Skill Challenges
It would be great to have skill contests in Career Mode, especially linked to the All-Star event or as monthly/pre-season challenges: shooting accuracy (aiming at targets), hitting the crossbar multiple times, precision passing, finishing drills, etc. These would add fun, help develop specific attributes, and fit the entertaining spirit of the MLS.
Salary Cap
There is no real salary cap implemented in MLS Career Mode. In real life, clubs must manage a strict salary budget. Without this mechanic, you can basically recruit as many players as you want without any meaningful financial restriction, which removes a big part of the strategic challenge that defines the MLS.
Designated Players
The Designated Player rule (allowing up to 3 high-paid players with reduced impact on the budget) is also not properly in the game. This makes squad building feel too similar to European leagues and loses the unique MLS identity.
MLS SuperDraft
There is no SuperDraft for college/rookie players. In reality, teams that finish lower in the standings get better draft picks for young American talents coming out of university. Adding a draft at the end of each season (with reverse order for bottom teams) would bring a real American sports feeling and help weaker clubs rebuild.