The only reason I would choose superior rune of the Centaur is to group swiftness buff (on every CD using medkit), and to get away from spending 10 trait points on speedy kit while keeping permanent swiftness (need medkit skill 5 as well).
This is exactly why I chose Centaur, and don’t regret it for one second.
i combined centaur runes with 10 in tools, 17 second swiftness O.O
maybe overkill lol, but i love it