The main Steam team has been reworking the download behavior, this isn't a Linux issue. You should mention your request in the main Steam forums so that it's tracked with the other feedback on the download changes.
implying anyone from Valve reads SPUF anymore
Ha ha, what a story Mark.
Closing as this option is at Settings -> Downloads -> Allow downloads during gameplay.
Nothing extracted yet.
You disabled the ability to download games while playing something? How about making it optional that user can effect. Not all games need fast connection. How the downloading should work currently? I can download only 2 games at same time?