I always said Panama existed, but shaped and located differently.
I didn't even notice the Panama Canal was completely gone in the A-Map. This poses a problem even if somehow history played out 1 for 1 in this "alternate universe". The Canal was built for two reasons.
1. Easier shipping between the Atlantic and Pacific, no need to go around the tip of South America. You cut large swathes of the trip out entirely, meaning you can ship more in less time.
2. The United States needed a way to quickly move around their navy. With two large coastlines to protect, the Navy was always split in two. If one side needed more ships, they had to wait a
very long time to get there. Those weeks or months it would take to get, say, a squadron from the Pacific Fleet to the Atlantic Fleet could result in an enemy force over-whelming the Atlantic Fleet and gaining naval dominance, and by the time the Pacific Fleet made it there it would be as equally out-matched as the Atlantic one was, meaning there was a serious possibility of a foe destroying the American navy piecemeal with a force half the size of the American fleet(because said American fleet's strength was always halved).
Another thing; again assuming that somehow history played out 100% the same up until a certain point, the
massive increase in distance between the Caribbean Islands and South America would've completely changed the warfare between the European powers in that region. Areas that were strategically important, even vital, in our world would not have been here.
Again, from a purely human-development and history point of view, this
makes no sense. Ignoring ecological differences, ignoring atmospheric differences, ignoring temperature differences, human history as we recognize it
could not have played out the same way in this world. It just isn't possible.
It simply isn't possible for me to over-stress how much different this world would be from our own.