Indeed it is sound Magicme. I have a zero cooldown zombie dog WD on non-seasons using some legacy gear from my time at release. Using zerodog there is no issue locking down a RG with Black Blood Sacrifice. Now with the new Homonculus the same can be done by multiboxers using at least 3 characters without legacy gear.

You are also right about other classes being able to do it, but I think WD still is the best because it requires no CDR whatsoever. The other two classes that can stunlock the RG (Wiz with freeze and DH with actual stun) require high amounts of CDR (59% for Wizard and I believe even more for DH). The other two classes that can CC the RG (Sader and Monk) use blind which still allows the RG to move around a little so it is a bit more annoying thatn hard stuns/freeze. Barb gets the short end of the stick in the fact that they have a great 4 second stun for the purpose, but like DH/Wiz it takes a lot of CDR to round robin and it has an additional flaw in that it requires the Barb to actually do an animation to use the skill. This means Barb multiboxers can't cast it while running without desyncing their characters (Saders have this same issue and theirs is directional without the shield for Shield Glare).

Utlimately, I feel WD will have the best option for CC round robin in 2.2. DH and Wizard are probably the next best two classes with Monk falling just after them. Sader and Barb are probably the worst in that regard. The main issue with Barb is not having a dps spec that can integrate the stun very well. All the other classes can use the stun much more reliably in a decent spec.