I think it makes sense for Heat Wave to have some kind of heat resistant suit given his weapon of choice. It certainly shouldn't be white and orange nor should it be made out of asbestos, but a costume makes sense for him to a degree (no pun intended). For the rest of them, I'd agree though. With the exception of the Trickster, bright and funky colors would look ridiculous on them. However, I'm not too worried because Boomerang looks to be taken care of nicely in Suicide Squad and he was one of the campier ones. We'll have to see how they refer to him in that movie, but that will probably set the precedent for how they handle the characters' names and looks.