Replace the strain penalty in flow with a specialised factor that relies on deviation

[kwotaq]

Currently the flow evaluator is holding the strain nerf for low spacing initially created to nerf "doubles" pattern maps such as Little Summer Party and Crystalia.

These patterns are broken when played unoptimally, practically disregarding the flow aim required and snapping between them while galloping. This is only possible to achieve either with tanking your accuracy or having the map on OD low enough that the extra hitwindow gives you enough leniency to do so which is why the highest pp plays on these maps are set with the EZ mod.

The live implementation of the nerf does not punish such play enough while also overpunishing correct play on the patterns. This change aims to create a factor to be used in performance calculation that relies on deviation, heavily nerfing attempts at using increased hit windows or bad accuracy to make the patterns trivial.

[stanriders]

Flow eval has low distance difficulty nerf because low distance is easy to flow just by its nature (sub-radius distances have close to no difficulty in flowing), not because of the doubletap maps

[kwotaq]

Flow eval has low distance difficulty nerf because low distance is easy to flow just by its nature (sub-radius distances have close to no difficulty in flowing), not because of the doubletap maps

Regardless of the intent the effects it has on maps are pretty clear, with cut doubles being completely gutted from it. I'd also argue the flow evaluator has no need for such a low spacing nerf in the first place.