Those scattered little Prussian... enclaves... are largely from PU inheritances from Milan, Bavaria, Oldenburg, Luxembourg (oh, the irony), and Hesse. I will, of course, continue to absorb other HRE members so that my borders aren't so... goofy.
In any case, I have most of the electors vassalized, and the position of Holy Roman Emperor is all but assured, which, unlike my first Brandenburg -> Prussia game, is a good thing because one of the ways of forming Germany in D&T involves being the Emperor. Most (~3/4th) of the empire has converted (forcefully or otherwise. Mostly the former) to Protestantism.
Biggest rivals have been the usual: Bohemia (now mostly neutered), Austria (pretty much neutered after a brief period of expansion-through-inheritances. They would've expanded into France, had the Emperor [read: me] not decided to attack them, ostensibly to 'free' Tirol and Switzerland.), Poland (that territory hungary has out east? used to be poland's), and Lithuania (...they guaranteed
everybody back in the day.) The only unusual rival has been Hungary, and only because of guarantees & defender of the faith hijinks.
Oh, and there was France, who tried to invade the HRE a while back. It... did not go very well for them. Just prussia alone would've been a match for them, and I'd already vassalized ~1/2 the empire by then, so... yeah, sucked to be them. Didn't even catch a break after the war, given that Austria immediately went after them with their full military power (~100k troops at the time, I think) while they had something like... 15k total. Would have been bad for both me
and France had Austria expanded any more, so... yeah, I intervened