Loading a save causes all units to freeze until the game initializes fully

Basically this. After loading a game, I often don't see the minimap (just a black box) until the game fully initializes everything, and until it's done all units are frozen, that can be abused against AI (cast a spell like Recall on your whole army to escape, etc) and regardless looks extremely ugly.

Suggested solution: don't allow the player to start playing until the full initialization, keeping him at the loading screen.