Whenever my group played p40 we always played no taking west usa before it collects and spends money. All the alpha changes did not change West USA being dominated, 2e did not change this as well.
On all versions of p40 you can take West USA without a hitch. After A+3 and 2e it got easier simply because aa guns do not shoot at everything instead they shoot 3 per, so only a limited amount of air gets shot at. Usually you just house rule it, but I can see USA starting with more AA guns without impacting global much. 5 starting aa guns should be good. Japan can still do it, but at least USA gets some shots off.
As far as global goes, lots of fun taking the axis up against USA.
I made the suggestion to allow China to leave China once it has all its territories for global.
~
I think 5 aa guns for west usa and China leaving China should suffice. You can experiment with that or at least allow China to secure the last part of the Burma road, which is India, but only if it meets certain conditions like reclaiming puppet state manchuria.