Don’t know, if it is in the latest build already, but it would be nice to have independent control of both. Might not be physically correct then, but still …
In our case a client would like to have the sunlight dimmed, but the sky should remain the same …
You can do that if you use one of the CIE sky models; you can also do it if you turn on the “manual sun node” option in VRaySky - even if you pick a VRaySun light there, you will still be able to adjust the sky intensity separately. And finally, you can put the VRaySky inside an Output texture and change its output amount.