25D is a bit much for me to test a brand new build.
I did roll up a budget version last night. The potential for single target dps is definitely there. And KBoF seems more forgiving than SS on how close you have to hug the boss.
I did have a couple issues that make me hesitate to continue playing. There's a bit of ramp time on the damage from the hex chance. This is ironically felt more during clear than single target in places that are unfavorable to KB(low density open areas). KB be might adequate for non-whisped rares most of the time, but once you're accustomed to how much more damage marking and hugging the target will do, that poorly signaled problem comes back again.
Maybe it's not "poorly signaled". Maybe I'm stubborn. I don't want to switch to single target skills while clearing a map. I don't want to even question, after killing a rare with my clear skill, would using my single target have taken less time?
I will say, thanks for the suggestion of Utula's Hunger and Immortal Call. I was having a really hard time combining Slayer, Penance Brand, and Spell Suppression. The Utula's Hunger package seems to work much better and is more passive point efficient.
EDIT: And most importantly besides the post below, do you have wither on hit? Huge difference there in output because of how fast this build can apply it.
So, I'll preface by saying I know exactly what you are talking about with being unsure of the viability of the build as a mapper, feeling like there is ramp time, and generally just kind of "getting over" the fact that KBoF feels so much stronger than KBlast when dealing with single targets.
First of all, it doesn't matter what skill you play, if you play KBoF EVERYTHING, probably even including Penance Brand of Dissolution, will feel inferior, but this is very much a "I think I need to get over having such good single target DPS that even incredibly good clear skills feel weak" problem.
Kinetic Blast, in practice, will feel very suboptimal without that Tincture. To put it into practical terms consider the following:
1) Kinetic Blast explodes 4 times on each impact, more projectiles = more explosions, much faster in packs
2) Each explosion is a "hit" and will apply the curses in an area.
3) When using Nimis, Kinetic Blast feels TERRIBLE, without as many projectiles as you can muster. Each additional projectile makes the skill, and the clear, substantially better.
4) Once you have enough projectiles splitting with KBoF in single target scenarios, there is no ramp time, even 10% chance to curse when you have 60+ projectiles hitting will essentially instantly "full" curse any target.
That tincture will make the playstyle feel vastly different. If you don't want to spend the money on the tincture, I'd play the BigDucks version instead. I've mentioned it quite a few times when talking about the Doedre's version of the build. The build does still work without it, but its the difference between "this feels decent, not a bad build per se" and "okay, this rips through everything".
You'll also just have to accept that you need to use both KBlast and KBoF in maps. There are no weapon swaps, it's not really a big deal, KBoF is just your single target skill and KBlast is your clear skill. Press R instead of E sometimes, if you get my drift.
Here is the original video from way back when with full juice
Poestack does make the process easier but there is a fairly high price of convenience for charged compasses in particular. In most cases when I use the regular bulk trade section of the poetrade site I can just ask the person Im messaging how many they have and 80% of the time they have bulk at...
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