Valve developer Pierre-Loup Griffais has tweeted out asking for information on Linux games that don't currently work with radeonsi.
Is anyone maintaining a list of Linux games that don't work on radeonsi? GL compatibility context, extensions Mesa won't implement, etc.— Pierre-Loup Griffais (@Plagman2) January 9, 2017
I'm sure a few of you have a list of games you know don't work, so why not let them know. They might be able to help Mesa get the games running.
Valve actually hired Samuel Pitoiset, a Mesa developer to work on radeonsi (source):
Samuel PitoisetThis is my last contribution for the Nouveau driver for a while because I have been hired by Valve to work on radeonsi. Do not expect such perf improvements with radeonsi because it already performs really well, unlike Nouveau. But with time and patience we can do better. :-)
So it's quite likely this list will make its way to Samuel to work through.
If anyone wants to keep a public list, I have setup a Wiki page for it.