The perception of delay is a lot larger for a single initial delay than a lot of smaller delays within the game. It’s very noticable if a game takes 20 seconds to get past the intro screens, while it is barely noticeable if a quarter of a second of delay is added to the loading between each level, even if it adds up to a lot more than the initial loading screen.
Considering that the use of 5.1 surround would be a very rare case for the target aidience, I find the choice of dropping it to be excellent to enhance the experience.