What if the Empire had come out on top? After Canossa, Henry IV had so much going for him. What if perhaps in 1081, he installs his Anti-Pope, and Gregory is perhaps captures, and dies on time in the Empire's hands?
I would imagine if the Papacy had been significantly defeated the world would be fantastically different even in just a few hundred years. The Empire would be much more stable (easier crusades?), the Popes would be more under the control of the Emperor. Consequently, the Emperors wouldnt have to deal with all the meddling with their Prince-bishops.
Even more long term: the slow separation of church and state, would not happen quite yet. The kings would remain in effect, the heads of their national churches.
Ideas?