I played German until 1940 and Japan until end of 38, Max help to the allies (I did boost Germany and Italy 1 notch in my Japan game)
I agree with Mike there are noticable improvements in a number of areas.As long as you keep the fronts fairly short the unit shuffling is reduced but not eliminated. I basically let the AI handle my front against the PRC and it played pretty well, with fairly minimal involvement The AI was quite good and shifting forces to where I was attacking but not over reinforcing.
The UK made a decent effort to defend the Suez and the Free French put up a strong fight in first capturing Vichy territory and the defending against the German counterattack. France fell quickly although it did last longer than the historical 6 weeks.
I attacked China as Japan as soon as possible May 36. I threw every unit I had at the Chinese. If I hadn't succeeded in surrounded the force defending in the Beijing area, I don't think I would have beat them. The AI actually recognized the danger and tried really hard to break out. I had a ring of cavalry south of the river near Beijing, the airport and Taijian (sp), My main force was pushing down from the NE, while the cavalry cut the supply lines and defended against vicious counteracts from PRC and other warlord forces. One of my cav units was down 10% strength. I played at speed 2, micro the hell out the attack and paused a few times. I was helluva of an exciting battle.
I conquered China on May 37 and while there were some places the AI let me walk into cities undefended, after losing 40+ division in the Battle for Beijing it just didn't have the forces.
I turned my attention to Dutch East India (in addition to all the yummy oil, and rubber, Borneo now has 50 Aluminum (woot a whole line of Zero's). It took 240 days for the war justification. When I invaded I got a nasty surprise. There were a moderate number of Dutch troops, making it not a cake walk. Then the bloody Russian sent 1/2 dozen armor division as volunteers who did a number on my Marines.
I didn't have a chance to use the conversion feature, not a lot of surplus tanks. I'm going go back to my Germany game and experiment.
The Air interface is a huge improvement. Way more intuitive and a lot fewer buttons to click and some nice information.
The AI manages its economy significantly better at the minimum they switch into the proper war economy.
The constant naval invasion by the Allies of NW Germany is still with us. Normally I have my troops in training garrison that area, but this game I add a full 24 division army and it didn't deter the AI from launch wave after wave of invasions and generally dying on the beaches.
It's nice to have different levels of puppets as the Axis
The Spanish Civil War last longer, it was still going on in 1938 in Japan game.
I'll try the expert AI mod, but I think this game provides a very good single player experience for WWII buffs after this last patch.
Edit: I finally figured out how conversions worked and why I was confused. You can only convert Base models to TD or SP or new tank but not directly to a new varient. So if you wanted to convert a PZ III to PV IV E you need first convert the PZ III to a PZ IV. The convert the PZ IV to a Pz IV E. I generally spend experience points as soon as research is done on a new model so I wasn't able to convert anything to it.