That's what made the buttons 4567, To avoid the same 1234 problem, This wouldn't fix anything but just cause the same issue of hitting the 6 simply because it's the first and closest button in reach
EDIT: better idea: the first option in voting should be "random map". e.g. when the voting starts, you can press 4 to randomly pick one of the nominated maps to play, number 5-9 are the nominated maps. Now there won't be a bias towards one map.