The main things I would like to see in regards to workspaces are ways to differentiate them. In Opera GX, you are able to set a custom color theme, but this stays the same across the two workspaces I have set up. This is the same with the new tab page wallpaper. For example, having a dark background & red accents for the procrastination tab, & light wallpaper, green accents for work.
(I don't think these features exist in the reguar Opera browser, but it would be nice to have in GX)
The other big thing is separate pinned sites (in Speed Dial) per workspace. Not much point pinning Facebook, Twitch & YouTube if they're going to show up when you're supposed to be working.