That concept can be done, but not the way in which you are describing. You can do Magicians with King Ahaz, split color EC's, demons that play any color and go that route. I did this before in a type 2 but used the interrupt and removes, JiP/Achan's Sin/Korah's Rebellion, and I used the EC's that could play any color as well as some of the main colors from their brigade and it worked awesome. I never tried it at a tournament but I'm sure it'd be a solid defense. But I am not sure about a mixed offense, when I do 3+ colors on my defense, then my offense is always one color to balance the deck out and vice versa if I do 3+ on offense, the defense is single color. So what it comes down to is I think a defense that includes characters that can play anything would work, but if you have that strategy on both sides it might not work.
