Ideas and suggestions.

Armageddon should definitely be a 5th-level spell, just like it was in "one of the versions."

In "one of the versions," there was experience for troops, and the stacks of Viv-Angels were also larger in number. Also, Antimagic was a multi-school spell, so it was present in almost all final builds. Because of this, there weren't any problems with Armageddon.