a few observations regarding China.

In the base game China "usually" does "well".
They get some rapid expansion building in their "homeland" unoccupied cities and usually this goes somewhat un-noticed (since they seem to be expanding "in China" ) but these centers are neutrals and are not Chinese per-se. China (usually) ramps up then is suddenly noticed by other big powers in the region. Russia, India, the USA, maybe even France or UK as well. Suddenly alliances are being made to contain China while China is making alliances to kill off some of these other major players. The way the game usually works is a few small guys are gone no doubt but those who remain at this time have some critical roles in who they will support (or they die if they make bad deals). When you take away a few powers, then you have fewer of these power brokers and the game is not balanced as well as it might have been.

Add China in Africa and not only do you make China stronger in Asia but it also ruins that power balance working in Africa (and Africa was a bit of a mess in the last games seeing China there).