Hrm. I'm not going to argue with you or call you wrong, because I will fully admit I don't know a lot about this stuff. "Art" isn't exactly my forte.
That said, I personally look at it and think it's fine - like, my opinion when I look at it is "Yea, there's nothing wrong with that". In fact, until about 5 minutes ago when more than 1 person said it wasn't good, I was rather proud of that banner. It makes me wonder where the disconnect is, where I look at it and think "Yea that looks good" and then other ppl look at it and go "Actually, that sucks".
And when you say things like "Comp is bad" I literally don't understand what that means. And the colors to me? They look fine. Again I'm not arguing what you're saying, im just saying to me, I don't see what you see, and I wonder why?
Also, I don't understand how that tool is useful. I looked at it for a few seconds, and without a greater understanding of what's behind it, I have no idea what it's even used for. In a minute or so of experimenting, I was able to manipulate it to provide any color combo I wanted. (For example I said "I want 2 blue, 1 yellow, 1 red, 1 green, then I moved them around a bit until it gave me 2 blue, 1 yellow, 1 green, 1 red. I then repeated that for 2 yellow, 2 green, 1 red). It just seems like you could easily manipulate it to provide any color combo you want, so I'm not sure what the point of it is supposed to be?