Reduce simulation thread load and network traffic by 20%. The disadvantages I see are increased lag on input and between a unit finishing one task and beginning another. The input lag can be counteracted in multiplayer by reducing the number of turns commands are delayed(COMMAND_DELAY_MP). COMMAND_DELAY_MP is reduced from 4 turns to 3 turns so it balances out increasing DEFAULT_TURN_LENGTH to 250ms with input lag going from 600ms to 500ms. Single player COMMAND_DELAY is 1 so it can't be reduced. Would just have to accept the up to 50ms extra input lag here. I played a quick single player game and found both input lag and lag between queued tasks unnoticeable.