Isn't that the point? People were actually trying to make a deck that could adapt to more situations than any others. However, like every other deck, it has it's weaknesses. ... Rainbow decks aren't perfect ...
So just to make sure I understand your line of reasoning. Because a deck has weaknesses or / and is therefor imperfect, it can not be overpowered. Is that it? perfection is a necessary attribute of overpowerness? I'd for one disagree, and for two: point out that if you also disagree you have not yet addressed the issues people are raising.
You're taking things out of context and blowing them out of proportion (that seems to happen a lot here, it seems). My line "...rainbow decks aren't perfect..." was an observation, and has no relation to my logic. If it was perfect, it would be overpowered. It's not perfect, but it is still very good. Rainbow decks can be beaten a number of ways, but really it all just comes down to luck of the draw. Just like how Mono-Aether can really only be beaten by a bad draw or deflag/steal/gravity shield, Rainbow can be beaten by deflag/steal/earthquake, and if you plop and Oty out soon enough, you could almost guarantee a win (I'm hoping that if you're playing Otys, you have creature buff, too).
I don't think we should really be arguing about how to nerf the rainbow decks just because people are biased against them (the point of the game is to have a strong deck, so why be a rebel and not use one?). Sure, rainbow decks are strong, they have weaknesses to be exploited, and are beatable, but overall, they can take on most standard decks. What I'm trying to say is that instead of trying to make rainbow decks weaker, we should make mono-, duo-, and tri-element decks BETTER.