The historical part is already on desktop, although on kinfocenter. I've been wanting to bring that to powerdevil too and I guess now it makes even more sense.
In an overlook it is mostly the same code (without the latest refactors I added), so definitely interested on some converging happening instead of multiple almost-the-same-but-not-quite codebases.
The main differences I can see is in presentation: one kcm with multiple pages on mobile, vs 2 kcms splitted into info + settings on desktop. I think at least the basic components could be shared when possible even if the entry pages differs.