There are a couple of different things to reply to: @Shyheels, I would like to put forth a hypothesis, and perhaps check on this myself when I get a chance. When we are saying, "fluid heel-to-toe motion" (or lack thereof), what springs to my mind from my own experience is lack of controlled heel-to-toe motion. Or not very much control, anyway. So that what you get, as best as I can put it without video or sound, is a ka-thunk, ka-thunk, ka-thunk. Does this seem familiar? I have another separate issue when I get up that steep, which I will save for later, as I have to work again this Saturday.
@higherheels Thank you for the measurements on the heels. I have actually seen a tape measure put to Hot Chicks in my size 40, and they are 13,7 cm. So I guess your boots in size 40 would be something on the order of 14,6 cm, which happens to be the exact height of my Pleaser mules, which I can barely make it across the room in. If you manage to master the boots before winter's end, mad props to you!
This month, incidentally, I'm going more for mileage than height, while the weather is still relatively nice. But I'm trying not to wear less than 10 cm on my walks.