Command Undead seems like a very powerful spell for a Level 2 Sorc. A Level 2 Command Undead gives zero saving throw against unintelligent undead, and gives a saving throw against Intelligent undead, but even then, they can just throw another one at the enemy.
I thought that Command Undead had a HD Limit. You could only Control Undead up to your HD. Unfortunately, the spell appears as if it doesn't have that limitation.
