Stick Sensitivity is a flaw, largely overlooked by the community. And, I know how it should be handled in the next game.
In the control options there is a setting called Stick Sensitivity. This name is does not a good job conveying what the setting actually does. To explain Stick Sensitivity I first need to explain how the game decides between if a tilt-attack, smash-attack, or dash-attack is performed.
There is a frame threshold for smash attacks. By default it is 4 frames for up & down smashes, and 6 for forward smashes. It doesn't matter how gently you press the stick, if you press the attack button before the threshold is up you get a smash-attack. Tilting the stick vs smacking it against the edge of it's range only determines if you walk or dash, and by extension whether you get a tilt-attack, or a dash-attack when pressing the attack button after the f-smash threshold.
The only thing stick sensitivity does is reduce the thresholds by 1 frame if set to low, or increase the thresholds by 1 frame if set to high. That's it.
To improve with utility and clarity of this setting, I suggest renaming it to attack balance. And renaming it's options from Low, Normal, and High to Easy Tilt Attacks, Balanced Attacks, and Easy Smash Attacks. Along with adding 2 new options Tilt Attacks Only, and Smash Attacks Only. Both of the new settings would use the default threshold for determine dash-attacks, but otherwise will only produce a tilt or smash-attack respectively when the attack button is pressed.