They’re both currently pretty much primary choices for vast majority of builds due to one reason or another.
Curse resist being compulsory on pub gaming (which is 90% full book runs) means that every character pretty much needs to have allocated slot for Curse Resist, ever since 2018. That is very stale piece of meta. Reworking how curse works would go a great way at making other options within that slot viable for use.
Swift Slaying pretty much is the go-to trait for vast majority of weapons because usually either there’s nothing more controllable/useful to pick or the weapons themselves are usually balanced by making them a bit slower people would like so combining both, SS is the primary choice to offset that.
Rather than cutting the corner and nerfing swift slaying (because i can easily guess FS would attempt to cap it just like other overly performing traits to proc once every X seconds) i would like to see more viable traits to increase variety and usefulness for individual weapons other than SS being optimal “there’s nothing better” choice for most cases.