Two weaknesses I noticed with axis efforts were one, lack of coordination between the axis (Japan couldn't assist against Britain, Germany couldn't reenforce Japan in China) and two Italy plain and simply could not prove it self as a true military force capable of attacking and taking territories like their axis counterparts.(Germany takes Poland, Japan takes Manchuria, Italy gets sent back in Greece) Suppose that Italy was that unifying force which could allow for troop movement, shipping weaponry and supplies between the 3 powers what would that have ment for axis efforts? I think greater coordination could have allowed for more aggressive and effective assaults on other areas such Britain and maybe even in the Pacific. Think of the Italians providing the Axis with a strong amphibious force able to attack effectively and rapidly fom sea to land. Lets say in this scenario also Italy wielded a capable Regia Marina and A Regia Aeronautica about half the size but just as well equipped as the IJN. Picture a facist Italy with a truly capable military top to bottom but particularly strong as a naval, air and amphibious force. I think had this had been the case a full ground assault on Britain would have been much more feasible with these type of Italian forces working together with Germany, almost having like having a piece of the IJN in Europe working along side the Wehrmacht. Furthermore dealing with the Italian control of the sea would have been priority one before landing on a German controlled France. Breaking the supply lines through which Italy controlled would have also been important in taking away the coordination between the Axis powers in Europe. Allied dominance in the air and sea was a big advantage that the Axis lacked having this capable Italian force controlling the seas and the air maybe would have only served to prolong the war or I think would have allowed for a quick capture of Greece and an opportunity for attacks on more ambitious targets after that.