(it's required for big reactors)

That doesn't mean if you're just using IC2 you still need it right?

I don't think we need it as a soft dependency. If big reactors loads, then the instance has cofh. Else, big reactors will crash. Am I missing some thing?

For Gradle for auto-installing stuff.

Isn't big reactors dependency on the RF api? I thought that was it.

Nope. It needs CoFHCore. See the site.