First of all, this may seem like a feature request, but in reality, it is not. The reason of that is that changing the game the way it is described here can be so much for a hassle. But that doesn't mean that things wouldn't be necessarily better if they were like this in the beginning.
Currently the score awarded for each Hit (which is affected by the Combo Multiplier) is:
HitValue * (Combo multiplier * Difficulty multiplier * Mod multiplier + 25) / 25
Which means that the max score of a song increases in a approximately parabolic way with the max combo of the song (a song that has, for example, a 600 max combo multiplier, can give almost 16 times more score than a song with only a 150 FC). Score is affected disproportionately by the length of the song, playing songs that are too short is a waste of time if you are interested in achieving score quickly, and playing songs that are long gives you so much score that it is unfair (this is one of the reasons some beat-maps, which would be otherwise be ranked, cannot be ranked).
So, to make a more proportionate formula (so the score increases in a lineal way with the max combo), we can add a new multiplier that corrects the current problems (the multiplier can be calculated after the beat-map is done)
First, we calculate the Maximum Score possible in the beat-map, and subtract the score that comes from bonus that aren't affected by the combo multiplier (for example, spinner's extra bonus points). Let's name this value Ma.
Then, we calculate the Max Score that would be achieved if the combo multiplier didn't exist (without the score that doesn't come from bonuses that aren't affecter by the combo multiplier). Let's name this value ma.
Then, we think in a value X so the value X * ma / Ma is close to one in an average beat-map. This value would be close to 6, so let's assign X the value of 6 (note that this value is completely arbitrary, it doesn't have an effect in the scoring balance).
So the new multiplier would be: Cm = X * ma / Ma.
And the new formula for hits is:
Cm * HitValue * (Combo multiplier * Difficulty multiplier * Mod multiplier + 25) / 25.
Examples of new scores (note that these are approximations, I don't know exactly what the max scores are):
Silver Forest - Marisa Spark (Insane)
Hits: 133
Current Max Score: 450,000
Cm: 1.63
New Max Score: 733,500
Score/Hit (Current/ New): 3383 / 5515
Silver Forest - Marisa Spark (Easy)
Hits: 71
Current Max Score: 48,000
Cm: 2.46
New Max Score: 118,080
Score/Hit (Current/ New): 676 / 1663
Yoko Ishida - paraparaMAX I
Hits: 5937
Current Max Score: 509,000,000
Cm: 0.05
New Max Score: 25,450,000
Score/Hit (Current/ New): 85,734 / 4287
Masayoshi Minoshima ft. nomico - Bad Apple!! (Insane)
Hits: 882
Current Max Score: 15,000,000
Cm: 0.32
New Max Score: 4,800,000
Score/Hit (Current/ New): 17,007 / 5442
Masayoshi Minoshima ft. nomico - Bad Apple!! (Hard)
Hits: 697
Current Max Score: 5,200,000
Cm: 0.40
New Max Score: 2,080,000
Score/Hit (Current/ New): 7461 / 2984 (note: this beat-map has a very high tick rate, which increases artificially the score a lot)
Shihoko Hirata - sky's the limit (TV Size) (Insane)
Hits: 387
Current Max Score: 2,150,000
Cm: 0.68
New Max Score: 1,462,000
Score/Hit (Current/ New): 5556 / 3778
Shihoko Hirata - sky's the limit (TV Size) (Normal)
Hits: 289
Current Max Score: 650,000
Cm: 0.88
New Max Score: 572,000
Score/Hit (Current/ New): 2249 / 1979
Shihoko Hirata - sky's the limit (TV Size) (Easy)
Hits: 187
Current Max Score: 210,000
Cm: 1.26
New Max Score: 264,600
Score/Hit (Current/ New): 1123 / 1415
Various Artists - osu! Stream Compilation
Hits: 4744
Current Max Score: 380,000,000
Cm: 0.06
New Max Score: 22,800,000
Score/Hit (Current/ New): 80,101 / 4806
Currently the score awarded for each Hit (which is affected by the Combo Multiplier) is:
HitValue * (Combo multiplier * Difficulty multiplier * Mod multiplier + 25) / 25
Which means that the max score of a song increases in a approximately parabolic way with the max combo of the song (a song that has, for example, a 600 max combo multiplier, can give almost 16 times more score than a song with only a 150 FC). Score is affected disproportionately by the length of the song, playing songs that are too short is a waste of time if you are interested in achieving score quickly, and playing songs that are long gives you so much score that it is unfair (this is one of the reasons some beat-maps, which would be otherwise be ranked, cannot be ranked).
So, to make a more proportionate formula (so the score increases in a lineal way with the max combo), we can add a new multiplier that corrects the current problems (the multiplier can be calculated after the beat-map is done)
First, we calculate the Maximum Score possible in the beat-map, and subtract the score that comes from bonus that aren't affected by the combo multiplier (for example, spinner's extra bonus points). Let's name this value Ma.
Then, we calculate the Max Score that would be achieved if the combo multiplier didn't exist (without the score that doesn't come from bonuses that aren't affecter by the combo multiplier). Let's name this value ma.
Then, we think in a value X so the value X * ma / Ma is close to one in an average beat-map. This value would be close to 6, so let's assign X the value of 6 (note that this value is completely arbitrary, it doesn't have an effect in the scoring balance).
So the new multiplier would be: Cm = X * ma / Ma.
And the new formula for hits is:
Cm * HitValue * (Combo multiplier * Difficulty multiplier * Mod multiplier + 25) / 25.
Examples of new scores (note that these are approximations, I don't know exactly what the max scores are):
Silver Forest - Marisa Spark (Insane)
Hits: 133
Current Max Score: 450,000
Cm: 1.63
New Max Score: 733,500
Score/Hit (Current/ New): 3383 / 5515
Silver Forest - Marisa Spark (Easy)
Hits: 71
Current Max Score: 48,000
Cm: 2.46
New Max Score: 118,080
Score/Hit (Current/ New): 676 / 1663
Yoko Ishida - paraparaMAX I
Hits: 5937
Current Max Score: 509,000,000
Cm: 0.05
New Max Score: 25,450,000
Score/Hit (Current/ New): 85,734 / 4287
Masayoshi Minoshima ft. nomico - Bad Apple!! (Insane)
Hits: 882
Current Max Score: 15,000,000
Cm: 0.32
New Max Score: 4,800,000
Score/Hit (Current/ New): 17,007 / 5442
Masayoshi Minoshima ft. nomico - Bad Apple!! (Hard)
Hits: 697
Current Max Score: 5,200,000
Cm: 0.40
New Max Score: 2,080,000
Score/Hit (Current/ New): 7461 / 2984 (note: this beat-map has a very high tick rate, which increases artificially the score a lot)
Shihoko Hirata - sky's the limit (TV Size) (Insane)
Hits: 387
Current Max Score: 2,150,000
Cm: 0.68
New Max Score: 1,462,000
Score/Hit (Current/ New): 5556 / 3778
Shihoko Hirata - sky's the limit (TV Size) (Normal)
Hits: 289
Current Max Score: 650,000
Cm: 0.88
New Max Score: 572,000
Score/Hit (Current/ New): 2249 / 1979
Shihoko Hirata - sky's the limit (TV Size) (Easy)
Hits: 187
Current Max Score: 210,000
Cm: 1.26
New Max Score: 264,600
Score/Hit (Current/ New): 1123 / 1415
Various Artists - osu! Stream Compilation
Hits: 4744
Current Max Score: 380,000,000
Cm: 0.06
New Max Score: 22,800,000
Score/Hit (Current/ New): 80,101 / 4806