You are exactly right in your chain of thought, I answered. By "exactly" I mean that you say that assertiveness is necessary. You do not mean that assertiveness is sufficient, you demonstrate that there are other links in the chain which together seem to be sufficient when acquiring respect for others.

I am ready to certify that there are therapeutic contexts when it is probably sufficient to focus on assertiveness and let it bloom when healing a timid personality. But I hope that assertiveness is not sufficient to achieve harmony in other contexts.

I propose a division of labor. If you like dealing with patients who are clearly diagnostisized as shy and debased by his environment you take care of these patients and give them assertiveness training which is sufficient for that particular therapeutic goal. I think you do not intend to sell assertiveness as a sufficient condition in conflict resolution.

The problem now is: is Shared Concern method a sufficient condition to solve conflicts? Theoretically I am inclined to say: such a thing would be impossible because I think that panaceas do not exist. Sometimes, assertiveness seems to be needed as a preparatory work before discussion about shared problems can start dealing with cases where shared concern is needed. So a division of labor in between therapists should be our way to avoid devastating conflicts but keep a proliferating dialectics going.