In the most recent row of discussions about Greater Germany and how to accomplish it, my PoV has been criticised as being too much Prusso-centric, and too neglectful of possible alternatives and the actual defects of a Prussian model that would get somehow expanded to Grossdeutchsland dimensions, my typical approach to the task so far.
Although I'm strongly persuaded that the Kaiserreich, despite its undeniable (but often overrated) defects, suffers by a lot of undeserved bad press, there may be some merit in the critique. So let's try and throw the issue wide open.
What would be in your opinion the most plausible/likely way and the best overall method (best for Germany first and foremost, and for Europe and the world secondarily) to create a Grossdeutchsland that endures to modern times, with a PoD between 1789 and 1939 ? Please make your argument both in terms of most likely and most preferable path. I'd also like to make the outcome of this discussion in a couple polls eventually.
"Greater Germany" for this purpose means a united German state that has to own all territories OTL Germany owned by August 1939, plus Danzig, West Prussia, and Upper Silesia. If the PoD occurs before 1919, it has to include Czechia as well. Elsass-Lothringen, Luxemburg, and South Tyrol are optional.
In order to be a preferable alternative to the OTL path, this Germany has to become as liberal, democratic, tolerant, and militarist as OTL UK or USA, and as economically, militarily, and culturally powerful as OTL Kaiserreich plus Austria and Bohemia-Moravia. They do not need be any imperialist (although they may), but a giant Switzerland equivalent is both way implausible and boring for foreign policy purposes. Of course, the 1939-1945/1989 catastrophe has to be entirely averted.