Figured I’d do a nice slow HRE game as Bavaria, limited expansion at most, mess around with my fellow princes, maybe enjoy a fun Religious War. Well, the Reformation had other plans - more successful than I’ve ever seen it, it flooded the HRE blue and went on from there. France? Protestant. Poland? Reformed. The only Catholic powers left by the end of the Age were the Nordics, Spain, Hungary and Naples.
Now, things got even more fun. The electors ran out of Catholic emperor options inside the HRE and voted for a blobbed mega-Hungary instead. The end result - all of the Balkans are now part of the HRE (I didn’t actually know that the Emperor’s lands joined the HRE, nifty). We Protestants easily win the League war nevertheless, leaving Hungary as the only long-term Catholic prince. And who do the electors turn to in this new gloriously Protestant realm? Yours truly, Bavaria supreme!
I decided to play the Good Emperor, liberating HRE states whenever possible, enforcing Protestant unity, generally bringing about a golden age for small Central European states. I was never personally too powerful, but my mass of allies and sometimes desperate military successes kept me Emperor and the HRE in decent shape. A member of the HRE was never actually directly attacked by an outside power, which was a bit of a shame. I could really have used that Authority reward.
Well, time goes on, I generally keep HRE states weak - I took great pleasure in dismembering Hungary over time and releasing all the Balkan minors - with the exception of my ally Brandenburg, who limits their conquests largely to outside the realm. Authority gain is a trickle at first, but gradually increases as I pass reforms and liberate HRE turf from Poles and Italians. And lo behold! I unite a massive HRE that stretches from Denmark to a stone’s throw from Constantinople. I look upon my loyal, adoring 36 vassals (Prussia being the only refusal) and feel content.
Then I inherited it and they all disappeared into a grey mass... ah, regrets. This was a very enjoyable ’slow, limited-expansion’ game. To be fair, I only expanded for like ten provinces total before the unification.