There should be an "Optimize Army" button or something which auto-selects and auto-places the best heroes for your army. It's infuriatingly tedious to sift through 70+ heroes and see which one of 7-10 slots they do best in, not factoring in if they're "Tired", "Exhausted", etc.
 "Heroes of the Realm"){kind=icon}
 "Dawn of the Dragons"){kind=icon}