I might not have a particularly strong opinion on this, and I might be way behind on the debate, but I guess I might as well try and post anyway.
It really depends on the players' unanimity of whether the charts are "boring" or "pointless". One way to look at it is that the rankings are made as a service to our competitors, since the competitors are the ones who are using the rankings. Therefore, we should try to form the charts/rules to make the playing experience better, whenever reasonable (while maintaining reasonable integrity of the rankings). In our case, I think all the cases (S1,2,3,&K and SAdva2) seem similar enough to lump into one decision; one would expect about 5-8 minutes of repetitive point scalping. So it's just up to the preference of those who are really playing the games.
If we decide to do something, then as for the options:
Make a rule - Making a rule against point scalping tricks generally seems too difficult, because repeatedly gaining points a few times (say 2 to 5) tends to be a natural part of gameplay, and making a cap is too arbitrary.
Delete charts - I agree with Zeupar that this seems better than the rule option. But sometimes people still enjoy playing with the point scalping option (or enjoy getting very high scores for the sake of it). Also, sometimes non-point scalpers may want to show their scores out of pride, even if it doesn't earn them the highest rank. I think these are legitimate concerns that a ranking charts system should address. Deleting the charts doesn't really satisfy these concerns.
Freestyle charts - For the reasons stated above, this would be my preference.