Hidden Power should have a major rework done to it if brought back.
This is what I would do a reworked version of it:
>hidden power can be either physical or special depending on which attacking stat is higher (like Photon Geyser and Shell Side Arm)
>an individual pokemon's hidden power type can be changed without limit via interaction with an npc, requiring battle points to do so, at 10
>base power is now 70 instead of 60
Wouldn't be OP considering that Fisheous Rend exists.