Hmm, this:
100% feels like it should be attached to Typhon’s Veil.
The awkward feeling after Fragment of Destiny receives changes but signatures don’t get buffed. 
…Kills off so many builds by making it specific to Twister. Etched sigil was already a fun, interactive item. No need to do this. I’d rather see Deathwish nixxed. 
This also leaves Twister channeling as a build, without giving the option of running non-channeled twister, while forcing every other build into a non-channeled option.
We want more options, not less.
Required modification of spell behavior. Why would I want my twisters to go straight? Circling back is what enables higher damage, and makes it easier to combine Raging Storms.
Twister weapon… Don’t we already have one of those? Tack the multiplier onto Twisted sword for pete’s sake!
Theoretically, a second weapon could make some sense if you’re offering an alternative method of non-channeled gameplay, but by leaving channeling in there for Twister, it becomes a requirement ON TOP of other multipliers.
Additionally, If I’m running non-channeled Twister, I’d prefer to have room in weapon slots for items like Echoing Fury or Aether Walker.
Could be interesting interplay for GR speeds, but seems like it will slow down our relatively immobile class by requiring to run a debuff skill. Highly mobile non-archon loadouts usually require Aether Walker, which usually requires AP restoring/reducing skills or items to supplement, and Teleport. Takes up yet another weapon slot (offhand).
Not that it’s necessarily a required item for Nephalems, but Nephalem rifting builds wouldn’t have the time to run this. Plant Hydra, Cast Signatures, then cast blizzard? No way that’s worthwhile.
Would require Frost Nova on the bar to use the rune, yet another skill slot requirement.
Chance also seems pretty low considering it’s an on-kill effect. Would much rather an on-hit chance effect.
I think i’d almost prefer something like:
Winter Flurry
This would benefit almost any build that runs the item, and doesn’t even require you run it on the skill bar.
Another weapon for Frozen orb, could be problematic for speed builds (as those also prefer Echoing fury, but I love getting those Wizardspike procs. Excited to test this change.
Good changes 
, even with Wizardspike, I think ~2.5GRs is a bit low for DMO, considering non-channeled FO doesn’t get the benefit of ES. Would be able to use area damage though. 
~2.5 GRs for TV seems just a smidge high if we’re making it competitive with LoN for lower paragons, but it’s great to see TV get potential buffs. I definitely want TV to be competitive.
Love it! 
Interested to see how having build changing AND environmental rift changing bonus mixes it up.
In summary: Deathwish still exists, Etched sigil is possibly gone, and we’re going into a season with a 4th cube slot. Channeled Hydra will still exist, but it will have to use arcane dynamo / signature spells and blizzard (possibly no teleport) with CoE burst. A very awkward playstyle when combined with channeling.
Would have loved to have seen more changes around Wizard’s mobility and more skills than just Hydra and FO.
Anyways, Looking forward to testing! 