@adamhcaldwell ,
I've also tried the rear foot lift by itself for probably half of the season before last. I liked it at first, but gradually grew to dislike it over time. I actually picked up some buoys when I got rid of the thing.
My theory at the time was that it made it more difficult to keep weight on my front foot during dynamic motions due to the increased relative length of my rear leg. I also ended up spraining my rear ankle many times for the same reason; well that and bad technique, but it definitely exacerbated the issue.
Thinking about it with a fresh set of eyes and going back to the analogy above/my opinions, it puts the feet on different planes. However, in this case we are stepping down to the front foot, relatively speaking. This makes it easier to shift COM more forward, but it forces the back leg/hip into a kind of funky non-ideal relationship as you said. I'm now thinking of it like going down stairs or running down a hill, sure gravity helps you out and does a lot of work (by definition W=F*ds), but it feels awkward and less efficient compared to walking or running on flat ground. So shifting weight dynamically when necessary may be more difficult/awkward, just a thought.
Maybe it's a premature conclusion, but based on this conversation I feel that we want geometric advantage which helps us shift our COM forward as much as possible/necessary, but while maintaining an athletic/neutral relationship between your feet, legs, and hips.