I think azure dragons will be cooler! :)
And here are the Lich Dragon parameters: 800 HP, 50-80 damage, 45 attack/defense, speed 16, but... abilities: 20% chance to block ALL magical and physical damage - that's ridiculous! These bastards sometimes block 5 attacks in a row!!!!! + they have a chance to poison the enemy like a wyvern + archer without a melee attack penalty with the attack of liches (cloud). Conclusion: Azure Dragon - bites hard, endures well, flies fast; Lich Dragon - clearly ate less, but ate something else that makes it feel no pain, often not at all (some kind of sadomasochist, you hit me, and I don't feel it: D), but that's a different topic and it's a matter of personal preference... (please forgive me for the off-topic).