Low level MRD, have a few questions

[Paikis]

Fracture is a gain of 2 GCDs in terms of holding hate on multiple mobs. You'd have to alternate HS -> SS on all the other mobs, whereas with Fracture you just need to toss one on each and you're good. Plus it's a pretty long DoT, so it's handy if your DPS is taking awhile on mob #1.

Fracture is terrible at holding hate as it doesn't have a threat modifier. It exists to do damage, not increase threat.