The mouse port thing is like a canary in the coal mine, betraying the people who just like taking shots at Apple, but generally are very ill informed. I think Apple should keep the port on the bottom purely so we can get the shortcut to discarding people's opinions when they hoist it up to concern troll.
For actual Apple Mouse users, charging is just the least concerning thing imaginable. The battery lasts an absolute eternity. I'm using one right now that I've had for at least five or so years and I charge it once in forever, it charges super quickly, and it's just not a factor in my life at all.