The reason for Rumor is that the other procs do more damage and something like Wind Devil should proc it with enough frequency for the RR. But it is mostly personal taste and shouldn’t matter too much.
As for new ideas on pets, I am more than willing to help turn any of it, no matter how awful into a working pet build 
(Note: Unless it is a Pet Hybrid or something like Physical Pet Warlord…)
Look who’s confirming everything I said!
Does it? Sure druid or warlock but conj? The extra pet is worth all those ranks?
It’s an aura pet, right?
Lol so it’s Nery’s build. 
And here I thoughts why it has no Ishtak, explains a lot.
Yup, on Conjurer. I ran a bunch of different combinations with Blood Orb, Solael Void Tome & Gate to see which one would be better since Cat’s Eye was nerfed.
While Blood Orb was the closest replacement, even with the loss of skill points, Gate to many worlds lead to faster SR/Cruci clears and kills on single target bosses like Callagadra.
The Pet is basically an Elemental Leviathan(whirlpool) Proc that scales off of Pet stats. It basically brings AoE dmg comparable to another Pet to the table with the only downside being a stationary Pet. And while I was skeptical on its viability at first, I must admit that Zantai did give proper compensation for the loss of Cat’s Eye.
Ishtak is nice devotion but doesn’t fit in my route to Leviathan.
1.1.8.1 update
GT - https://www.grimtools.com/calc/O2G1e7GZ
Crucible run of 6:02:
SR 85:
Mogdrogen+Ravager
Nice variation of the build! In my version I’ve focused on getting % all damage to pets (including cold) to get some decent clear speed, also few procs. I like Shepherd’s Crook devotion but it’s hard to it in Ishtak’s path. Your build looks easier to play with less keys, which is good thing.
Also superb visual illusions! 