SavoyTruffle said:
Would it result in the refracturing of France, a more unified HRE, or just general mayhem in Europe?
A defeat at Bouvines would be disastrous for France, but I don't think it would lead to the refracturing of the country. By 1214, the country was firmly in the hands of Philip Augustus and the Capetians. Besides, Philip Augustus has a son, Louis "the Lion" : the French nobles would probably rally to him if Philip was killed at Bouvines.
On a side note, a victory at Bouvines would not be convenient for Otto IV... He was already excommunicated, and he led the attack at Bouvines on a Sunday. Sunday being the day of our lord, Christians were forbidden to fight during that day. Otto would thus alienate him most of the Catholics.