Well I guess it depends how the overall score would be calculated.
but for your overall rank, only the normal points you would get considering the overall points you have.
This for example would defeat the purpose of the idea, which wasn't to give us a score on each map, but to take into account your skill on each map to calculate point loss, therefore avoiding you to lose a lot of points on map you've no idea, and making it way more difficult to reach top of the scoreboard by playing only one map.
The OP didn't develop much the first post so I am speculating a bit but I believe I was right on his intention.
In this case, how would the overall score be calculated ?
If the overall score is simply the average of all your score on each map, then yes, a point reset isn't necessary for high ranked players, you are right WingCmdr Ginkapo .
But I think it would be much more difficult to reach such high overall score as the one we have now, and therefore would be unfair to low rank that would try to reach the top.
If the overall score is simply the average of all score on each map, people already having a high score just have to avoid playing easy map ( classic, doodle, luxembourg but also any map on which they can't maintain a high score), to keep their high score. I know they already do it but it doesn't matter because other people can do it as well and reach the top of the scoreboard.
But if the overal score become the average of your score on each map, someone starting tomorrow with 1000 points on each map, to be able to reach a 2500 pts score, he would have either to reach 4000 pts on half of the map, or reach 2500 points on
each map. Both would be really difficult.
So in this case a scoreboard reset would be necessary to give a chance to other players to catch up with high ranked players.