The idea here is to create a new bang that does the same as !RainmeterMoveMeter, but that the movement is gradual (i.e. animated movement from A (current x,y position) to B (new x,y position)).
!RainmeterDragMeter [X] [Y] [Meter] (Config)
Moves the given meter (i.e. not the window, but the meter) gradually to a new location from the old location. To achieve a smooth animation it is advised to have low update rate, but it should be noted that this can affect your performance greatly.
I'm certain this solution would be a lot more resource friendly than earlier approaches (Here (see Extra Example), here and here.).