What's the problem with that? If the game is balanced around the idea that Japan needs to attack at the early, historical time, I count that as a plus.
Maybe you can argue that world tension increases too fast in the early game, but that's quite a different issue.
Historical time would be July 7, 1937, not May 1936, as it should now be done in every game.
Also if it comes to world tension increase: conquest of China takes a month or two, half a year if you have bad luck. So if you go to war in May 1936 it ends before 1937. And after you annex/puppet China it's over 50 world tension and your game is over, because American player has just awoken his industry. You can of course just wait and start the sino-japanese war in 1938 for example, but thanks to buffing China you'd get bogged down unable to divide your forces to get China and Dutch East Indias at the same time.
What annoys me is that Paradox again took the easiest way out, which a also bad choice. They just added equipment and factories. There are several great mods slowing Japanese conquest (and this is all about slowing japanese conquest of China) by using events and focuses that add National Unity, moving factories to west China, fortifying bigger cities and making them very hard to take. This way the war moves from plains in the east China to mountains and deserts in east, south and north China. And that makes Japan bleed out of attrition and slows them down considerably boosting the chinese defences.
The war lasts longer, is harder and much more fun for Japan player.