Suppose the cavalry doesn't rout and the Tercio isn't wrecked by artillery barrages, how would things change if the French lose this decisive battle? It's been said that the French were a fifth column during the wars of religion, but if they were officially forced out of the war I still think their privateers/brethren of the coast in the Caribbean would still disrupt resource extraction from the new world and help facilitate Spanish decline. With that said a defeat might end their destabilization of Catalonia. Whether that leads to a preservation of the Iberian depends on whether the British had already come to the aid of Portugal.