You forget mentioning Brooks. Zoro was so angry to Sanji and Nami for letting Luffy recruiting Brooks the first time they met. Zoro is a character that doesn't trust people the moment they met. Zoro need more interaction to believe people. Zoro doesn't want to save Kinemon at PH at first, Zoro doesn't want to save Vivi, heck even saving a litte kid and a lady Zoro need discussing some terms. Zoro doesn't have the abilities to read people heart like Luffy and Sanji (mostly with women but Kinemon in PH shown Sanji can care for male also)