Banshee for sure, possibly Scorpion as well. They're not slouches to agility either. As much as I want to play a Reaper main, I find myself giddy to be a Predator stalking SM's and Orcs:
Looks really dumb to be honest. I know it's not meant to be on the FD, but it shouldn't be on any class. Makes the Eldar feel cartoony, not to mention actually doing that in the middle of a warzone would be pretty counter productive. Do what Relic did the the Autarch in DOW2 Retribution, just leap over minor cover. Don't make it automatic though, that would mess with the cover system.
From what I have read eldar hold themselves far above any other species in the galaxy and are prone to showing off. This flip is what I would expect from a race that feels there is no equal..even though said race is being torn apart and going extinct through there own action
I mean I would assume a member of a race that's barely clinging to existence would be making smart decisions instead of doing unnecessary flips that would ultimately hinder them in combat, rather than aid. I honestly don't think you could be arrogant enough to do that.
I don't see it as counter productive. It's quick, and agile, just like the Eldar. You make your way over on your feet again, basically not removing yourself from a standing position so you can get on the move again.