It would be really nice, and useful, to be able to change the viewport colors (and alpha) of materials.
Being able to distinguish which material is used where is really useful, and could speed up the workflow (reducing confusion etc).
Right now we have to switch the render to Cycles, change the settings and then switch back to Octane, it gets rather annoying and slows down the workflow a lot.
I tend to have several similar materials (like outer glass and inner glass, etc) and having a fast way to see which is applied where reduces a lot of troubleshooting and not having to wait for the render to clear up before you see that's the wrong material.
Since the Viewport settings isn't directly connected to Cycles, I hope it's not too difficult to copy over/implements for the Octane material panel.
(Thanks to the devs for all their hard work!)