4-9-2 Legalistic Obedience?

Joshua was very good at obedience to clear commandments (Josh. 4:10,17; 8:27; 10:40). But when he had to articulate his faith in God in unexpected situations, e.g. when the ambassadors from Gibeon arrived, or when the first attack on Ai failed, he seems to have performed poorly. Legalistic obedience is no use in those cases when principles need to be applied. Josh. 5:13,14 can be read as a rebuke of Joshua, wanting to boil everything down to black and white, wanting to see God as either personally for him or against him; when the essence is to seek to discern and do God’s will. He very strictly adhered to God’s commandments with legalistic obedience, e.g., about how to approach and deal with Jericho, or how to cross the flooded Jordan and build an altar; and time and again, we read in Joshua of how he strictly relayed and obeyed the Divine commandments given by Moses (Josh. 8:31,33,35; 11:12,15,20; 14:2,5; 17:4; 21:2,8).  Yet as with any literalistic or legally minded person, it was hard for Joshua to apply the principles behind the laws to situations which weren’t specifically addressed by Divine revelation, where legalistic obedience wasn't what was required.