If there wasn't a Reformation, there could not be a Counter-Reformation. The Church would not be motivated to clean up it's act until it was too late. Too late for what, you might ask?
Scientific knowledge was continuing to advance in Europe, often under the guise of magic. The Catholic Church was becoming more and more corrupt and more and more riven by factions based in countries, specifically at the time between France, Spain and the Holy Roman Empire. And classical knowledge, including knowledge of neo-Platonism and gnosticism was increasing and out of control because of printing. Ship captains were even bringing back exotic texts such as Hindu Vedas and Upanishads and Buddhist Sutras, although there was a lag in translating them into European languages.
If Orthodox Christianity was not reformed, literate and educated people (who were a larger and larger fraction of the population each year in Europe) would look for religious answers outside of orthodox Christianity altogether in areas that would be considered heresy. As they say about guns, if thinking is heretical, only heretics will think. Illuminism (thinking like that of the Bavarian Illuminati) will flourish and be relevant in a way that it never was ITTL. Albigensianism might be rediscovered, as might Luciferianism. And a lot of these ideas might get real political patronage by kings and nobility who are on the outs with the powers that be in the Catholic Church and are looking for a new set of ideas to motivate their people. Eventually, a new set of religious wars.