Yeah, surprisingly (or unsurprisingly, depending on your POV) there have been very few major players stepping in to convert their historical or recent titles for Linux. They are probably waiting and wondering if there's any good reason to do it... If the Steambox ever sees a release based on a Linux environment, I would expect things to change, though.
Most games make most of their money very shortly after launch so the ROI to do a port probably isn't there unless there is a very compelling display of demand. There are some AAA games that don't make it onto the PC at all, let alone Linux.
The best hope here would be that valve could take some of the games that are known to work flawlessly with WINE and package them up with Steam handling all of the WINE config so it becomes transparent.
It will be interesting to see if a popular AAA franchise (elder scrolls, COD etc) announces a Linux release alongside the Windows release.
As game devs have to think more about crossplatform I guess this might become more likely.
