Its worth noting that the moment Nynaeve showed her weave to Heal Siuan, the Yellows started discussing ways to use Earth and Fire in healing problems. One started talking about using fire in problems of the heart (which is obvious... electrical rhythms can be restored with Fire) a minute after she saw that Fire was safe to use in Healing.

Later, we have Egwene say that the Yellows had taken what Nynaeve had made and created a marvelous set of weaves.

All this points to me that Yellows are far from the picture that is painted of them. Notice that Suana has a herb garden. It seems to me that Healing as weave only is a concept only non-Yellows subscribe to. Yellows, I think, are happy to use anything that helps repair what is broken, and were held back by Tower tradition and lack of experimentation rather than affinity for specific Healing.