The cape itself looks a little too metal for me and hard surface.. if that's correct explanation what I mean. Like lots of capes look clean when just moving like there is wind. Comp cape looks like real fur or cotton, whatever material it is.. this looks a little too metal, I guess that's because their lightning.
Which is also something I disliked when they started reworking stuff like : Hellhounds, varrock guards, abyssal lords, cerberus outfit, couriers, .. Clothes shouldn't really reflect or have that shiny effect when turning around.
Some jmod said (and I believe it's on the website and wiki), that he himself or they are looking in to it. I asked on reddit if it would be possible like it now is in-game > RGB colors, to not choose one colour, but choose three colours. My example was Red to red, Green to black and blue to red > so it would be red black red smoke (slayer vibe). If I can remember correctly, I got the reply that was not yet possible due some feat...