The only flaw I can find with the game was probably the emblems, which if you got the right combination literally made your army invincible. The leveling wasn't an issue because the computer was set at the average level of your entire party, however by adding the emblems the level equality gets taken away.
For example, by the end of the game you could have made your main group entirely angels with all the buff emblems and basically move the entire field to kill off the enemy in a single turn.