1942 looks a lot more fun to me.
First of all, it’s likely to be a bit shorter. After all, they are further along in the war.
Second of all, China has a good double the amount of units they have in 1941. 9 infantry and 1 fighter vs. 4 infantry and 1 fighter (in 1941, Japan could destroy China with relative ease).
Third, Japan has less sea power, so America wont be destroyed if they dare step up to Japan.
Fourth, Italy is setup the same exact way in 1942 as in 1941, but with more units on the Italian peninsula.
Fifth, Canada has more units on it in 1942. Canada will never get more units (likely), so it is nice having them start out with more so they can play a role in the war.
It just seems that all of this, especially China, will make the 1942 scenario play better.