Do not know do you have a free time to implement it, but it will be good.

Current factories do not support options saving somewhere,
so for every factory floor we need set all those: items on overlay controller, exchange speed and direction - for power, pipes - all of them.

But I think you can put multiple (STANDARD item!) constant combinators near factory floor exits and power station, and keep all configuration inside them as signals.
Next, you can mark them as indestructible, not mineable, and not rotatable.
If so, we can use blueprints to save factory floor options with buildings. I mean if we apply a blueprint with signals saved, it should apply them into those indestructible constant combinators. And even more - we can save factory buildings with their configuration for the floor.

Why separate constant combinators for every factory floor exits - to support a blueprint rotation.
So, if we have some signals with 0/1 for a direction, and some another signal for rate/power value - it can help with all options.
Also, it can give us more precision in values for rate/power values.

+1 to this. The current state of the mod is absolutely amazing, if it was blueprintable and had output icons on top of that, I'd say that would be uncomparably best mod of all, no joke.

I have even better news: I plan to overhaul the connection system using new API features such that configuration will no longer be necessary at all. Pipes will use the upcoming linked-pipe entities, which uses vanilla fluid mechanics to form a connection. Belt connections will use similar linked-belts, circuit connections will just connect directly and bidirectionally, and power connections will also be bidirectional. Chest connections are the only remaining scripted connections, the update rate will be dynamic depending on the amount of chest connections in the world (N chest connections will be updated every tick, N is configurable in settings), and the transfer direction will be defined by the logistics type of the involved chests (example: connections will always point away from a requester chest).

As a bonus, this will decrease Factorissimo's idle UPS requirements to basically zero.

Chest connections are the only remaining scripted connections

Aren't there already linked chests? those were first. Or do they not work for this situation.

Linked chests exist too, but their mechanics are not particularly suitable for chest connections, and there is no such thing as linked logistics chests.

I have even better news: I plan to overhaul the connection system using new API features such that configuration will no longer be necessary at all. Pipes will use the upcoming linked-pipe entities, which uses vanilla fluid mechanics to form a connection. Belt connections will use similar linked-belts, circuit connections will just connect directly and bidirectionally, and power connections will also be bidirectional. Chest connections are the only remaining scripted connections, the update rate will be dynamic depending on the amount of chest connections in the world (N chest connections will be updated every tick, N is configurable in settings), and the transfer direction will be defined by the logistics type of the involved chests (example: connections will always point away from a requester chest).

As a bonus, this will decrease Factorissimo's idle UPS requirements to basically zero.

Oh my god.
Yes. Please. 10/10

So, how goes this project? It sounds awesome!

It turned out linked-pipes are not actually upcoming, which kinda put a damper on things. Maybe I'll ask for source access and add those myself if I find the time.