yeah, leveling, especially when playing solo self, is all about juggling life, resists, and skill slots. I very much think that is one of the games big successes. it IS very hard to get a BIS item. and what is BIS for one build is NOT for another.
1.6k sounds a bit low for act4 cruel. But, I don't really pay close attention to that. could be remembering wrong.
Skill is a big deal. most of who have played over and over, really can zzzzz through alot of those early fights. dodging stuff becoming second nature.
I stacked a ton of defense on my frostblades. Fortify on FB itself, high priority. Frostblades-Multis-WED-Fortify. (added cold, inc crit)
+enfeeble/blashphemy. high priority.
+enduring cry. high priority.
+immortalcall/cwdt/frostbomb. low priority. frostbomb very low priority.
+decoy totem. Broken op vs some bosses.
FA+whirlingblades+ancestral protector. ancestral protector is high dps. when you don't need decoy.
+dual heralds ice/thunder and ice golem of course.
I also was pathfinder, so that Elem DR, immunity to status effects. And flask priority was granite/jade/sulfer/silver, and 1 life flask. I do NOT run acrobatics. Flask effect on granites or rumis is better imho. Also, this thing,
Perseverance - Official Path of Exile Wiki dont have one admittedly.. but, yeah. would be GG for my frostblades build.