Could the War of Spanish Succession had ended in the Hapsburgs retaining the Spanish Crown (including Sicily, Naples, Sardinia, and Presidi) but France gaining the Spanish Netherlands and Milan?
France gaining the Spanish Netherlands and Milan?
You could swap Milan for Naples or SardiniaThe former would be a direct threat to both England and the Dutch Republic. The latter to Austria. Hard to see everyone agreeing to this.
You need to have Carlos II do not change idea about his heir at the last minute and so keep Charles of Austria as his heir but France will likely obtain Naples and Sicily (with or without war) not Spanish Netherlands and not Milan (who likely will go to Austria, the Duke of Savoy or the Duke of Lorraine instead of France or staying Spanish)That's exactly otherwise of what was proposed in the Treaty of London: Spanish Netherlands and Sardinia, French Naples and Sicily and maybe Milan depending on what happens with Lorraine. The treaty was ratified by the Netherlands, France and England, but Louis XIV couldn't contain himself in asserting Bourbon claims to the Spanish throne and triggered the War of the Spanish Succession. We would "only" have to revert the Treaty and for France to cause a smaller war with Austria and naming it "Spanish War of Succession".