Thanks for the replies!
That's cool, though I guess I'm more referring to the natural way I can work with channels in PS, not just for PBR stuff but for work with particles and shaders. Like being able to select a channel and paint straight into it, or adjust its levels, or run other filters per channel directly.
Yeah I think that's like the PNG export I mentioned, where alpha 0 is black in the exported image. I think the fix for this is to have your alpha channel as a mask at the top layer, and a solid colour layer at bottom (at least for PNG this seems to work). To be fair PS sucks at this too, hence SuperPNG which does it for you using an actual channel in your document.
Installed the V2 trial and had a look and yeah that is kind of nice!