Tactics for playing as the Dwarves.

Hello! I choose Erling as my main hero because he has magic skills, and gnomes rarely get them. I level him up to become a lucky wizard and choose the "battle to the last" skill, meaning I learn Armageddon and Pyrokinesis. I attack the enemy a few times, placing dragons and Armageddon units to attack individually. I would like to hear all the pros and cons of this tactic. Also, the Rune of Impenetrability is very helpful.