As someone who doesn't know how to duel I had more success turning my brain off and spamming swings with cyan than I did creating an Anki deck to memorise SeV's dueling guide and trying to meticulously use yellow.
You are probably right that there is something to cyan that makes it a menace. I don't know what it is, because I don't really understand the system. I wouldn't call for its removal, however. I'd sooner see the developers create some harmony between all these stances. I like the idea of variety.
As a bit of trivia, with cyan's stationary D swing, the animation causes you to lunge forward. There it has both more range and speed than red. At least it was this way when I tried it on a dummy. This will probably have no practical application in dueling, but it is amusing.