There are quite a few things u are missing from what I saw in that video:

  • U are using F&R and no generator which means u are missing a ton of DPS. Get the Endless Walk set + CoE and u should do much more damage, and also help with survivability while moving around.
  • No perma ignore pain. This is a big one. U should have it 100% of the time, specially while moving around when positioning to the next pack. Not just because of the DR but immunity.
  • Autocast your EB. U forget to cast it and keep losing the buff. Use the numlock trick or whatever works for u so its always being casted. Same goes for other buffs/debuffs from your party that can be casted while moving (blinding flash, warcry, ignore pain, etc.). Looks like u cast them just before engaging and that's a big NONO. That's why u got 1 shot by that Lacuni.
  • Diamond Skin seems kinda useless there. Maybe go with Frost Nova for additional 33% debuff or Familiar for more damage.

AND, the biggest issue of all: POSITIONING. This meta is all about positioning. Your twisters were always going all over the map instead of going in a corner and stacking the damage. Just play solo in any map and test by yourself. Its fairly easy to aim and get them to not move much. U also need to move around, pull a ton of mobs and only then start killing them. Illusory boots or Wings of Angels might be a "must have" to make this work.

If u dont pull a ton of mobs and stack your twisters in that same spot, the spec wont work.