Expedition's End Lightning Shenanigans in shambles

I dropped said Body Armour early into the league and got very lucky 6-linking it. For those who don't know, it's the Heist Unique that lets you freeze with all damage at a higher effectiveness. Now what I'm trying to do is combining the strong freezes with high damage rolls of lightning skills and because I love the skill I'm going with Arc for the moment. Here's the PoB of my SSF Templar:

https://pastebin.com/xeRyauTb

While the plan to instafreeze Sanctum Guardians up to T16 map bosses works really well there are some roadblocks that are hard to overcome, namely Essences and everything that can't be fully slowed. Much of my survivability is owed to enemies simply not moving most of the time but once they do my lack of burst damage or strong secondary defenses really shows.

I have some ideas to improve the damage output but so far haven't managed to craft a good +1 Amulet, Wand or Shield. One more accessible option could be to balance Strength and Intelligence so I can drop Increased Crit for Crit Multi. The passive tree could be really wrong but whatever changes I did try seemed to only make it worse.

​

My questions: Is giving up the Body Armour slot for the unique effect simply not worth it? Could it potentially work if I changed the skill? Did I overlook accessible damage/defense options that would make Arc viable?

Again, I'm SSF so +1 Fractures, T0 uniques and such are probably not within my reach.

edit: Here's the PoB of the overhauled build:

https://pastebin.com/93ubv8Gp

In addition to the suggested changes I balanced Strength and Int for more crit, got a Guard Skill and Culling Strike on the Golem. Feels much better than the original and I can... Recommend it? Well, maybe that goes to far but it works for T16s and Sanctums now and that's what the build is for.