You're going to have a Greater East Asian Co-Prosperty Sphere consisting of Japan, Manchukuo and Siam. Possibly Mengkukuo(Outer Mongolia) and Jingwei China depending on your POD.
That's hardly going to be a dominant bloc, unless Japan consolidates and effectively dominates China. Even then they're still going to be dependant on US goodwill.
Imperial Japan basiclly had to expand to survive, and the Co-Prosperity Sphere was just a nice looking public face to that. Japan would rather puppet a land than outright conquer it as to better combat the partisan problems.
As for this bloc lasting until today? I don't see it. Japan basiclly had one of two options by 1940 when the US cut off the oil. They could capitulate to the US and West in exchange for economic prosperity, or they could take the resources they need it.
Given their attitude of the that Japan won't stand back for anything, it's hardly surprising that Japan went to war.
But if you're bound and determined to have Imperial Japan around after WW2, they'd have to reach some compromise over China with the US. Possibly a puppet government based out of Beijing, recognition of Manchukuo & Mengkukuo in exchange for a pledge of no more interference in the Kuamantang's government in Nanjing.
So that'd give you Japan, Manchukuo, Mengkukuo, Siam and a rump China. Hardly a coalation the world will fear. Japan would probably go nuclear by the mid 50's but as the Cold War starts, they'd eventually find themselves more and more on the allies side.
You could see a Korean War type conflict over Mongolia, or possibly China as a whole if Mao can manage some more victories over the KMT.