Complex sentence: Although a professional--captains at the time were almost exclusively amateurs--the respect in which Hobbs was held meant that he was accepted as a captain, and many, although not all, critics considered him a competent tactician and leader.
Split into simpler sentences: Although a professional--captains at the time were almost exclusively amateurs--the respect in which Hobbs was held meant that he was accepted as a captain. Many, but not all, critics considered him a competent tactician and leader.