It's true that resolution and circle size are related like that, but any incidental movement (eg shaky hands) has its effect amplified more the smaller the circle size is. Yes, increasing the tablet size solves this issue in theory, but one can only play with a tablet area so large, and most people play with roughly the largest area they feel comfortable playing with. And the reason people try to play with larger areas is just that; the larger the area, the less of an impact shakiness has. Thus, I think on the higher end (cs6/7+) the circle size really tends to get underrated.
The other thing I want to say regards the recent changes. The reason that longer maps should (and now do) have the scaling factor is because your chance to miss and the amount of time required to fc drastically increase as the map length increases. This is irrelevant if the map is a fairly routine full combo, causing long maps that are easy for the player to become overrated. This is not important in most cases, as a map that is a routine full combo for the player will not be worth a significant amount of pp to them anyway.
However, it causes problems in the extreme case (~2500+ combo). The scaling on long maps continues to increase, meaning that a player can gain a significant amount of pp from a map that they will practically never miss on, given that it is long enough. This is clearly seen in the world's end map that pielak referenced earlier. The pp awarded is pretty clearly too high. With that said, I think the changes worked wonders for anything in the 1000-1500 combo range. The bonus for map length simply needs to begin to taper off around 2k combo, and I think the algorithm will be in an excellent spot in terms of accounting for map length.
The other thing I want to say regards the recent changes. The reason that longer maps should (and now do) have the scaling factor is because your chance to miss and the amount of time required to fc drastically increase as the map length increases. This is irrelevant if the map is a fairly routine full combo, causing long maps that are easy for the player to become overrated. This is not important in most cases, as a map that is a routine full combo for the player will not be worth a significant amount of pp to them anyway.
However, it causes problems in the extreme case (~2500+ combo). The scaling on long maps continues to increase, meaning that a player can gain a significant amount of pp from a map that they will practically never miss on, given that it is long enough. This is clearly seen in the world's end map that pielak referenced earlier. The pp awarded is pretty clearly too high. With that said, I think the changes worked wonders for anything in the 1000-1500 combo range. The bonus for map length simply needs to begin to taper off around 2k combo, and I think the algorithm will be in an excellent spot in terms of accounting for map length.