It's reasonably simple to switch configs in Affinity but it still involves closing everything and restarting the app. You can't have two documents open that need different configs.
It'd be great to do the setup of a few configs once and only require a restart when you change that setup. That way we could have open a few documents that are in difference OCIO colour spaces. I often have to switch between nuke-default and ACES nowadays. Being able to set and save (in Affinity format) what config a document used would be great and only like two or three lines of extra meta data. It would also make it easier to work in larger teams and bring work from multiple sources together.
Then having an OCIOconfig node/layer which could be used to transform work from one base config to another would be really sweet.
Being able to toggle through configs would also be great for last minute jobs where everybody just assumes you know their workflow and eff-off right after emailing you the logins.