Dealing with can openers is an aspect of the game. In terms of balance, give the game a bit of time to develop.
I’ve yet to see British sea counters to a German Sealion. Once this happens consistently, the game will settle a bit, the Americans will have a better shot in the Atlantic and will be able to focus some serious naval force in the Pacific while maintaining a transport shuck in the Atlantic. That will balance the game. American worries Italy while the British pound France as the Russians reel from a German assault, trading land for time as the Japanese war machine slowly grinds to a halt in the Pacific.
That’s the way it should be, and that’s the way its going to be. Heading all out in one theater isn’t an option anymore people. Get used to it. Heading all out in the Atlantic means Japan wins by J4. Heading all out in the Pacific means Germany wins by G6 or G7. The Allies cannot focus on one front. The rules don’t allow it.