If Japan did everything she did in the OTL AND sank the German East Asia Squadron, she's going to be even more angry and humiliated at Versailles when she's patted on the head, handed a biscuit, and basically told to fuck off while the "real" nations get down to business.
Agreed. They'd probably only get a couple extra U-boats or something equivalent for the effort too as reparations. Maybe they'd be U 151 or U 139 class ships, but frankly, anything besides getting treated like the Major combatant they were would have been highly insulting. Especially if they had also sunk some of the major commerce raiders of the war, including the
Emden. (Of course, that would have major butterflies if Müller survives the war intact, and the Emden was as successful as IOTL, since he'd be one of the few major german war heroes to make it into the 1930s and 1940s, and might become a Generaladmiral or even a Großadmiral.)
Maybe the Army gains a bit more political capital for the Showa period, while Baron Kamio Mitsuomi doesn't die as quickly, and his sense of caution sinks in with the general staff?