So, I may be one of only a few, but I have always kept my 2.0 click up on my pet. It boosts the dps, even if not a large amount (60dps or so on an EMVIII pet at 85 is what I recall). I've almost always kept Hobble buffed as well.
At what cost though?
In underfoot, there are many blue and white con mobs, and stuns are the boss method to mitigate damage - far more powerful than slow or attack debuffs. Our pet proc line has a 1.5 second stun (to lvl85) attached to it.
With Hobble and our buff proc (Spirit of Vaxztn), I had a 5.5 ppm proc rate on the pet. This is 8.25 seconds stunned per minute.
With Vaxztn alone, I had 8ppm, or 12 seconds/minute stunned.
I didn't get specific numbers w/ 2.0 and vaxztn or all 3 together, but Vaxztn is driven significantly lower by the high procmod on the 2.0 click.
These stunned figures are slightly optimistic - Vaxztn landing too closely together can lose overall stunned time, but I saw that happening maybe 5% of the time on the mob. Resists are a potential issue too, so we'll need to pay more attention to the resists that are on our proc lines for future development.
So, if a blue or white mob is doing say 2000dps, Vaxztn alone can potentially reduce damage intake by 20% or 400dps. That's significant.
We also can expect more procs of 2nd spire and/or bp click buffs if we don't have our 2.0 up, which will make up for at least some of the dps loss from not having the double attack mod that our epic gives.
I've made up my mind....2.0 is getting banked.