As I replied in your other thread the Surface Pro has a smaller screen, makes things complicated.
I'll be traveling so I compared the older Surface Pro that we have with the other laptop, a 13.3" HP Spectre 360. The weight difference is only 6 oz for a bigger screen, better battery and for this generation difference more power.
Even on the 13.3" things are busy on LR, in Photoshop is even worse. Power is not the great either. Works for travel and some light editing but not for a main machine.