for gameplay's sake, having germany united by a bunch of rebels would be game breaking. in real life it took until the late 1800's - in game it could happen almost immediately.
First of all Prussia and it's allies (nowadays northern germany) were pretty united at the 1700s an besides currently what happens is
in the 1419-1500
-small unions: hannover annexes oldenburg etc.
- burgundy conquers dutch provinces.
-bradenburg is swallowed up by the polish.
-Austria vassalizes/annexes Baden, Strassburg and bavaria
-france annexes lorraine,cologne and some others
1500 - 1600
- France continues it's triumph takes hannover, palatinat and some others.
-Austria gains holland(inherits burgundys lands)
-Austria creates a land bridge between dutch provinces and the german ones.
1600 - 1700 only a few german states left:
-Austria in war with france mayde some new germans declare independent after wars, become vassalized afterwards
1700 - 1821
-Poland collapses prussia takes over the german provinces
-religious wars new germans declare independent after wars, become vassalized afterwards
So it would not hurt to help the germans a bit would it?