The ability to extract from item loaders
it would allow more control over loading systems.

Going to need a more detailed use case than that.

It would be useful for any rail system that has multiple loaders, is backlogging or simply wants more control over the amount of items its sending
e.g. The current system i am working on
The system above is meant to keep a massive controlled backlog of items ,but there is no space for comparators and i cant measure the amount of items backlogging in the loaders
There is no real reason i can think of why extraction should be prohibited and i see plenty of uses for it.
(if its balance reasons you could only make it available on the advanced ones)

Use chests? Loaders will pull from adjacent inventories.

I was not aware of this
Thanks

Or use a AE2 Network,