Soldier gives some very useful defense, and a big AS boost. More importantly, it gives 2 WPS (weapon pool skills), one of which is buffed by Rah’Zin’s. Judging by your build, you’re unfamiliar with the importance of WPS: they allow ranged attacks to penetrate targets (well, some of them do), and their damage stacks with the default attack replacers, additively for flat damage, multiplicatively for %weapon damage. Here is a great primer on the subject Turbo-charge your auto-attacks with default attack replacers and WPS. It’s a bit old so it doesn’t contain penetration info since that was added in a recent patch, but it explains it really well.
In summary, the percentages add up (until you get over 100%) so in this build, 90% of the attacks will utilize one of the four options: 16% Burning Void, 18% Blazing Fury, 27% Markovian’s Advantage, and 29% Zolhan’s Technique, while the remaining 10% are default attacks. Markovian’s Advantage and Zolhan’s Technique apply some pretty substantial debuffs as well.
Let’s run the damage numbers on the best WPS for this build, Zolhan’s Technique: the basic attack is Touch of Chaos, which does 133% weapon damage + 33-135 chaos damage. Zolhan’s Technique does 238% weapon damage (with the buff from the build) some small internal trauma damage that can be ignored, and 50 chaos damage. If I understand correctly (99% sure I do), the 133% and the 238% get multiplied, for a total of 317% weapon damage, plus 83-185 flat chaos damage on top. To make it even better, this super attack will penetrate targets (I think no more than 6). Basically, if you’re using an auto attack build (that isn’t cadence), the biggest factor in your damage output is WPS.
Your build doesn’t have WPS, so it will do maybe half of the single target damage, and far, far less against multiple targets. It should still be reasonably strong, given that my build could clear SR80 before they added penetration to WPS, but it won’t be top tier. (also, you should take the last 10 points out of arcanist and put them into a skill, probably overload. Skills > attributes).