I've already complained about this in another question, but having open digital distribution systems would be glorious. This encompasses both patching systems and end-user marketplace type things. Steam handles a lot of this, but is far from an open platform. Even if it wasn't a single shared marketplace like Steam is (or how phone marketplaces are going), having a solution you could easily rebrand and deploy for yourself would be a huge step forward (assuming people actually did things like submit patches upstream and all that FOSS goodness).