I haven't had the opportunity of installing the 2017 Tech Preview yet. While I find the moment to try it out, I'd like to read some comments from those of you who are already trying it. Does the announced "GPU / 3D Graphics Performance, accuracy" for Metal GPUs have any relevance for OS X/macOS guest hardware acceleration? For instance, would running Snow Leopard Front Row be possible at all now on a Fusion 9 virtual machine in Sierra or High Sierra?
Unless they did something magical, I doubt it. I understand that it's a limitation in how Apple built the graphics subsystem in OSX - there's really no hooks for acceleration in the older versions.
I'm not sure if we'll see acceleration for newer OS versions - maybe they can pass metal through to the host? But if they had that kind of feature, I'd expect it to be highlighted in the release notes, and it's not.