I'm not entirely sure why but I've heard a few people say something like that. I can't find any solid reason to support that claim and several reasons to show that new brigades are a bad idea.
One of the clearest to me is how it messes with the closed categories. It is awful to draft a new brigade when only 1 of the packs has that brigade because of the imbalance. I remember drafting silver wasn't so good (unless you got lucky with TSA or Captain) when only a couple packs had silver. By Angel Wars the imbalance wasn't so bad but then with Priests it was even worse. I think pretty consistently the worst tins to get in draft were teal or orange because there is almost no support for that putting you at a disadvantage. This is one of the reasons I've really wanted the new set to be a well balanced traditional booster pack set so we could have better drafts. The new brigades also make those packs a bad choice for sealed.
I think all the excitement of a new brigade can be captured by having new strategies or themes in existing brigades.
I think I agree with red for offence. For defense I think brown, pale green, black, orange, and gray are all used pretty frequently. This seems to me to leave gold or crimson as the least used.
