Philip II Capet, King of France, from 1180 till his death in 1223, was one of France's most pivotal historical characters. He was very skilled at politicking, negotiating, and manipulating other important noble figures within France and her surroundings, and eventually succeeded at breaking the chokehold imposed on the capetian royal demesne by the English in the west (in the form of the various semi-independent fiefdoms they held in Aquitaine, Anjou, Maine, and Normandy, and their overlordship in regards to the dukes of Brittany) and the Holy Roman Empire in the east. He even managed to dedicate some spare time for subduing the County of Toulouse to his south and preventing it from falling to someone else's hands. His key battlefield victory at Bouvines even had debatable effects on English history, as it encouraged the barons to pressure king John Lackland into signing the Magna Carta, setting a precedent for decentralization of power away from the king's figure. The subsequent rise of France as a power also shook the foundations of Europe for centuries to come.
But what if Philip Augustus had never risen to power, replaced by someone less competent or imposing, or at least was much less successful in his plans for increasing the power of the house of Capet? What would this mean for European history there and after?
Could the Angevin Empire survive and even grow? Something tells me the English nobility would sooner or later protest their junior position within the composite monarchy, but would there still be a consolidation of the political institutions that resulted in England's parliamentary system? Would it eventually absorb the lands of the Capetians through marriage after sidelining them in the western European political stage? I'm convicted that the Angevin Empire could have become a significant maritime power in the centuries to come.
Does France's continued fragmentation have any effect on the Iberian states?
What about the Holy Roman Empire? Otto IV was a Welf, a house traditionally allied to the Pope against the Hohenstaufens, but quickly showed himself as likely to adopt aggressive and centralizing policies as, say, Frederick Barbarossa. Could this trend continue if there's no growing France to throw a wrench in the German (and also, to an extent, Italian) machine?
Any other consequences of notice? Could French have not risen as a prestige language?