I kinda agree with you anyway, Palatinate and Mecklenburg should go in, maybe Baden and Oldenburg as well. The problem I'm seeing is that it might become easier for the strong neighbours to conquer them one by one. Strong army <- money <- towns <- space on campaing map. If they can be made to work, I'd like to see as many as possible.

Maybe the HRE could be represented by all the German states being protectorates of each other with full military acess...