Lightroom CC for mobile: Impossible to batch rate photos

You should be able to do it in the Library module Grid view

As Paul says, it only works in Grid view. If you're in Loupe view, even though the filmstrip shows multiple photos selected, your work only gets applied to the active image (the one in the main window and the brightest one in your selection.) 

I see now that you're referring to mobile - I agree that this would be useful, and I don't see a way to do it.

Should this get more traction form mobile users for Adobe to consider it of is this feature planned as feature parity continues to improve?

In addition to the original request I would like to suggest being able to flag / star upon importing via the iOS shortcuts feature.