A lurker to these hallowed boards. I find myself mulling over the war of Spanish Succession, and can't find any threads that address my exact line of thought.
Suppose Charles II of Spain, famous for his physical, mental, and emotional disabilities, had not been so handicapped.
Or suppose rather, that his half-brother, Balthasar Charles, had succeeded the throne as Charles II instead, rather than dying to smallpox in his teenage years.
In either case, the main POD being the continuation of the Hapsburg line in Spain, and an absence of War of Spanish Succession. What will a competent (if not fantastic) Spanish monarch do with the waning days of the Spanish Empire?
Balthasar Charles surviving would lead to a clean succession from Philip IV, while OTL's Charles II would still have to deal with his mother's disastrous regency, competent or not.