Thank you for this information ... is there some place where I can track the development of the "GPU rendering details system" and, more specifically, the implementation these wind/detail overrides?

As for the resolution proposed ... how long do you think it's going to be before we see this in an update? Your best rough guesstimate will suffice ... this has been an issue for a long time now.

The bending of the grass over a large terrain area produces a wave pattern that moves across the grass in a single direction only. There is currently no way to get the wave to move in a specific direction (i.e. with the wind) and/or link it directly to a WindZone. One could argue that each grass prototype should have it's own rotation setting, just like trees do, giving the developer infinite control over each prototype vs. simply linking a single WindZone to the terrain that controls every grass therein.