Good point, didn't think about it as I always try to maintain a "healthy" AE level.Well, if we're talking about a good player taking the min-maxiest approach then you're right. Forming the HRE is just better.
Still, it's not to hard to imagine a situation where you just sort of started a game with no plan and got a little province hungry and ended up with most of the provinces to form Germany and -200 or more aggressive expansion with most of the electors. That's actually really easy to do as a country like Brandenburg. Forming Germany could be a much more practical thing to go for in a situation like that.
Actually, I think that currently, Germany as Emperor with privileges revoked is much stronger than the HRE tag.Forming HRE is stronger, and has always been stronger, assuming you can actually pull it off. Obviously countries like Brandenburg, Bohemia and Austria have a big incentive to attempt to unify the HRE instead of forming GER, owing to their starting advantages inside the imperial system.
It still seems to me that with the new patch, forming Germany will feel much less rewarding in the long run than going for the HRE. There must be something to make it more worthwhile. Most of the situations you guys have described are cases of Germany being a "consolation prize" because you either screwed up (too much AE causes electors to hate you) or you're not eligible to become the much better HRE in the first place (wrong religion/government).