In simple terms: poorly. Up until the war, the German Empire could trade on the fiction that it was a federation of princes, a system in which one royal house exceeded the others in power by degree, but not kind. Subjection to Prussia was acutely felt in some quarters, but the imperial centre was always careful not to rub it in, actually went out of its way to keep up the pretense that the Grand Duke of Mecklenburg-Strelitz or the Prince of Reuss in the Junior Line was a brother sovereign ruler who had voluntarily abdicated some functions of that sovereignty for the greater good. Now, the imperial centre has run roughshod over all that. It was made clear for all to see that the word of of a Corps commander outweighs that of an imperial prince, that the emperor and reichstag can decide whatever they choose as long as it touches the safety of the reich (and everything does, ultimately), and that any decision made to apply in Prussia will quickly be used all over Germany because that is how political gravity works. They built railways and enforced production quotas, price controls and rationing, standardised schooling and pulled millions of people from their village homes to show them the world (or at least the part of it they were currently fighting over). All resistance to modernisation was ended by fiat. There is zero tolerance for the quaint, the venerable or the eccentric in this new order. And that is before we even get to the economic and social impact. Some princedoms managed to make themselves comfortable in the new role of a federal state. Hamburg and Bremen make money hand over fist trading on creatively exploiting the limted options they have. Baden and Saxony are big enough to retain a cultural identity that can be fully German, yet clearly themselves. Bavaria is too big to do that comfortably and there is friction. But a lot of the old order is crumbling. By the end of the century, the Prince of Waldeck-Pyrmont, though still wealthy and living in comfort, will have about the same real-world importance as Punxsatawney Phil.