These are all workarounds, I tend to play the game in my living room where people are watching TV, so the only way enabling sounds when the game is minimized would work is using headphones, and unless I really need to I don't really like playing with headphones.

A simple desktop notification (or flashing icon) would be a much better solution, also if you think about the bigger picture, if a deaf player is playing then the sounds are a none option.