Selective masking using luminance in Lightroom cc as in Lightroom classic would help speed up editing. Is this on the plan to be added in the near future?
Lighroom CC, Lightroom Classic and Camera Raw are all based on the same raw engine, so it's safe to assume that anything in the develop module of Lightroom Classic or in ACR will sooner or later make its way into Lightroom CC as well. In fact, Lightroom CC already reads and applies the Range Mask on images that are synched from Lightroom Classic with this feature. The only thing nobody can and will tell you is how long it will take. There is still a lot of work to do in Lightroom CC, so don't expect everything to appear overnight.