[quote=Bright_Ops]
I always viewed that fight in the context that Celestia was holding back due to all the innocent ponies that were around them while the fight was taking place. Roasting her loyal and loving ponies by accident seems like the kind of thing that would haunt her.
[/quote]

Hmmm true you make a valid point. Then what about when the citizens were running around scared for their lives. Think about it at that point all was pretty much lost so why would Celestia still hold back when she saw her subjects being terroized. You'd think she would have brought the Sun's Wrath -que fist shake- down on the bugs.