Mouse charging location

Nope, I don't.

I doubt Apple is thinking about that but that's an unsubstantiated opinion on my part. Apple does change ports from time to time, but history shows the locations do not change substantially.

No, because the top of the mouse moves and having a port on a moving, up and down, surface was probably tested and rejected.

To charge my Magic Mouse I plug it in at night every now and then to a self powered USB A hub.

when I first got my current iMac, I had the exact same thought. but after using it for a while, I found that I can go for almost a month before the mouse needs to be charged. so I usually use the mouse for about two weeks. after that the charge remaining is at about 50%. it is then that I plug it in overnight. that way I don't need to worry about needing to use it while charging.