I think what may be missing is the concept that the speed is increases at the point of the transition, not on the way up. Obviously you will always loose speed going up, but that speed has already been gained passing through the transition. The orientation of the transition doesn't matter either, it could be up, down or horizontal. You go higher up the wall because you enter it faster from the transition.
To put it another way, by pumping, you leave a transition with more speed than you entered it, regardless of it's orientation or the grade around it.
Sure, we can say that, but it is only in the Y direction that you can increase the speed. I think that was discussed before when I explained the difference between speed and velocity.
However, this effect is much smaller than the raising of the CoM. This is the same speed increase you get when you jump the terrain feature I showed before. A small increase due to the new Y component while the X component stays the same. In the example of pushing at the beginning of a curved ramp however, the x component will decrease quite rapidly.
You could say that the major reason you get higher is that the COM is higher when you enter the ramp, not because you are going faster.