I could potentially see the logic behind the sensor feet on cloth pad, but that totally depends on the materials used for Cloth pad.
not to mention what surface you use UNDER the mousepad itself.
I use a XTRFY Mousepad with a mirror surface beneath it, and I can tell you now that the pad is smooth as butter and totally straight, no bendings or wavyness anywhere.
Quite interesting as about all mousepads including this one are rolled up in their package, the XTRFY's come out quite nice and are easy to make straight.
As for zowie feet are terrible, I totally disagree with you but again that is totally personal preference and depends on what games you play imho.
I have two mice, one with Microsoft Explorer hyperglides (5 pieces) and the EC2-A stock's replaced with appropriate Hyperglides, and i can tell you the zowie is smoother and glides better (less friction)
Both mice are about the same weight (give or take a few grams)
Bigger feet also make less dents in the cloth pad altho with XTRFY the material barely allows any downward pressure.
The game I play requires precise tracking even at very slow speeds, so i need as much glide as i can get no matter what speed i track on.
On a side note, tanaka's ebay pads are good, and for plastic pads I doubt it matters, but on cloth the hyperglides are just so much better / less friction