Gotta say I respectfully disagree here. Does the new Mighty Mouse look ridiculous while being charged? Yes. Did they take the lazy/pragmatic route when locating the Lightning port? Undoubtably. But is there any chance that Apple would launch a mouse in 2015 that is meant to be used while plugged in? No way.
The new MacBook is meant to be used completely untethered from its power source. Same for the iPad and iPhone. If Apple put the port in the head of the mouse, people would absolutely leave the thing plugged in 24/7, all dragging that cable around their desktop like an animal.
Yes, this is willful (spiteful?) design, but it’s wholly consistent with their current design direction.