They all have made their mistakes. Only thing I blame Saul for is leading the Mallers to the location of the Tower. They did not know where till they followed Saul back.

Other then that lack of judgement. He is devoted to his people. I do not think anyone else has the devotion he does. Others have their fixation. Saul would do anything for any of them.. He has IMO a too big of a heart and it will or maybe his demise.