Well, but if I am understanding the hybrid bonuses correctly, the player will get hybrid bonuses by just getting 2 levels in a different affinity. So, the hybrid bonuses kick in even if you are not equal in two affinities. And, if I am 10 purity, 2 supremacy and 0 harmony, I will get the purity/supremacy hybrid bonuses even though by your definition, I am not a hybrid affinity.
And my general point is simply that BERT will encourage mix affinities. Going 12/0/0 for example will no longer be a viable strategy.
Don't get me wrong. I love the hybrid affinities. I am merely making an observation about how BERT will radically change gameplay.