you need voice of dragon 3 to get +2 moral to dragons, you will need rage control if you want rage for your pet dragon, you need might runes for destruction 1,2,3. I don't know what to tell you. I use dragons when I play safe, I do damage with spellbook, I don't really care how much damage dragons make
I rather cast fire rain that does 4000+ damage then have 50% critical on dragons
play as you like, there are many ways to play this game, voice of dragon is one of them
And critical hit chance is not the main purpose of +2 morale on dragons, defense and attack are
Critical chance you boost with items like axe of lightning that gives +10% critical chance to ANY unit in your army