This has the possibility of being an add-on idea.
Currently, there is no mechanism to split deck presets automatically.
But what if we make Anki show the level of Difficulty Distribution for each preset as a health indicator.
Where two presets share similar parameters,
- A healthy preset has cards with not so much variation in their difficulty. They are all within a narrow range
- A bad preset has cards with very varied difficulties. This is an indicator that the user should probably have to split the deck into subdecks and group similar cards together to assign them a separate preset.
This can be shown as a health box indicator under FSRS.