* Actively collecting statistics for WebGL and organizing by GPU. (WebGL stats, etc.)
* Letting a user submit a 'something's wrong/slow' bug, and having info on what hardware it is.
These don't require unconditional exposure. This can be gated behind a user-accepted doorhanger/permission dialog.
Notably, something similar to Valve's hardware survey would work fine with this mechanism.
* Use the driver/gpu info to estimate performance.
This can be accomplished by getting permission from the user to query this info the first time, then stored.
I would go further, and say this is a much softer requirement than most people believe. Most every game from Flash up to triple-a titles have a long history of letting the user manually select a quality (performance) level.
* Driver X doesn't handle Y properly, so we want to do something different for driver X.
In an emergency, just work around it unconditionally, if possible. (generally possible)
File a bug!
Notably, we've had numerous instances in the past where developers think a driver is buggy, but it's actually spec compliant, and the devs were relying on non-spec assumptions which held steady for only *some* drivers.
Assuming, however, a real issue, this is ideally the browser's job to handle: We're supposed to be offering a consistent API. This is huge, saving everyone else time and money. The pragmatic issue is that it takes more time to ship workarounds to users via the browser than just pushing a patch fix to production.
Selfishly, I'd love it if somehow people were forced to bother us if they hit a driver bug, and it would probably even make the web better for having been reported. (though this is clearly not a good motivation to force compliance by this mechanism) I have discovered the presence of a number of bugs only by overhearing grumbling about them. (Please report bugs! Or at least email us about them)
I think having it gated behind a permission request would solve all major issues.