I think your brightly-coloredness concept at least correlates with the concept of kitsch, and I think both of these correlate with works that represent their constructed worlds as simple, direct, and comprehensible, rather than complicated and “realistic”. things that are kitschy/brightly-colored and funny are straightforwardly funny; things that are kitschy/brightly-colored and dramatic are soap operas. I think it’s about how abstracted the constructed world is from reality.

I see what you’re getting at here, there’s probably something to it on some level – most kitschy stuff is likely to be brightly-colored? – but it’s eliding something important.  Arthuriana is super “shrouded” (not-brightly-colored), for example, and it’s very simple and direct and non-realistic.