Some things have been improved with AI in 2.6, for example there's logic to save up for a fleet now.
An other good reason for hopefully not waiting some more years to release 2.6.🤞
Yes, although I won by round 5 this time (thanks to some luck and the fact that I assume the AI does not see the Economic Victory at all), it does seem that 2.6 plays significantly better than 2.5 in this game overall.
Saved game, played with 2.6.14492:
There has not been a need actually to save income for future shipbuilding.
By the start of the second Germans turn (Germans having 3 bombers and 4 fighters), the AI had in North Sea Zone a quantity of units which put the Germans at 84% win and +16 TUV swing. This actually means that I would have averagely lost the 4 fighters and saved only the 3 bombers if I would have got the 84% win (and of course had a 16% chance of disaster). That was just enough to convince me not to attack the sea zone. I don't know if the AI actually didn't fail while failing or actually and quite correctly decided that even those bad odds were actually good enough (because in the specific case the Germans TUV is just worth so much more than the Allied one). Since the air was very much needed for the land, I didn't even attack the lonely battleship in West Mediterranean Sea Zone, but that is mostly me being very cautious. However, the AI could have assured better odds while still killing all my Germans ships (the way I described previously), so maybe someone can look into it if there is something to improve or the AI actually (correctly) reasoned that an 84% for the enemy was actually good enough in the particular situation (I doubt it).
By the start of the third Germans turn (Germans having 4 bombers and 5 fighters), the AI had in North Sea Zone a quantity of units which put the Germans at 53% win and +19 TUV swing. Again, I didn't attack.
Overall, winning as Axis by round 5 in Classic with no bid is certainly not a good result for the Allies, but I actually think that the AI played maybe decently this time. A bit of this outcome is actually to be credited to luck: on round 5 the Russians attacked East Europe with a 92% and +7 TUV swing which actually ended in retreat and a -18 for them. If that battle had some close to average result, I would most likely not have won so early.
However, regarding the previous game, I do believe the very bad fail of leaving Russia (Moscow) at 99% Win for Japanese is a serious issue also in 2.6 as I tested the save and went the same way (as I said). I definitely believe something must be working wrongly there if a developer can check that: you can load the previous save (not the one at this post) and see that British just moves the air units away letting Japanese have Russia (Moscow).