i suggested something like that here
if you break it up then the score for each setting needs to be calculated independantly of the score for every other setting. that way it is not possible to bomb a stack of Assassin games to lower your score to make a run at No. 1 Terminator.
The two suggestions, as I understand them, are identical; except that you wanted a point reset, which I think is outside the bounds of realistic expectations.
As for the whole win percentage idea, I don't think that's a good idea. On top of it being a relatively useless metric, IMO, I think folks are right that there would be even more incentive to farm than there is now. Additionally, the threshold should be set very high so that someone can't come in and win 18/20 games by luck and remain at the top of the scoreboard forever. Perhaps one fix, if you went with that and wanted to keep the threshold low would be like the current scoreboard rules, where you have to have finished a game in the last 30 days to qualify. But I think that's another topic for another suggestion.
Finally, I like the idea of having different nomenclature ("King of XXX") than Conqueror. Kind of a neat tweak.