We'd like to use a rotating scoreboard on our server but we're not sure all of the people on the server would be happy with that. It'd be awesome if clients could individually switch it off, and optifine is already used by pretty much everyone on the server!
My "feature request" at the moment is being able to play ViveCraft (the VR Headset Mod) which ships with Optifine to back it, AND Fabric mods providing the client-side stuff we like to use on our server. Today is not that day, unfortunately. OptiFabric, Fabric in general, and ViveCraft do not play well together.
I personally think that Vivecraft compatibility is a thousand times more likely to become a reality than a very specific and circumstantial server-related feature that does not fit the scope of this mod at all.
Please keep in mind that this compatibility may not only be Optifine's burden to bear, though. There's probably lots that Vivecraft and Fabric (perhaps even Forge) can do on their end to make this a reality as well.