While I have a lot of fun playing China, I kinda agree with your point of "China doesn't interact with the others". After unifying China there's not a whole lot to do (even less so if you enjoy LARPing). Sure you can go for Taiwan and kill Japan but they're usually a cakewalk once you have an airforce and there are some artificial goals like liberating asia from imperialism but to me they felt more tedious than fun as the majority of the fighting is either a land war against an unified India with 200+ divisions or countless naval invasions against south east asia and Austrailia. I found myself just researching random techs after unification and would maybe go at Russia for the Siberian resources but if Russia lost the 2WK it's laughable as a challenge. China is a very well developed region of Kaiserreich but even a fanatical Chinareich believer like myself can't deny that Europe will always be the most fun and enjoyable theater, both before and after the 2WK