[Djones]

about the time the mobs are all casting and clumped. I get 3-10 second delay on responses. If you need me to replicate I can do that.

Find me as Djones, or Tettanus

Edit: I was told a month ago or so that I should petition this, I thought regular patches may improve it over time. But I will try to describe what I am experiencing better.
I did some more kites last night. This time incrementing up from 60 - 110. Also went and did a 2 kites in OT.
At about 80 mobs (30%ish are casters) The Desync begins, But is manageable. What I see on my end is the major clump of mobs following me but not where they should be. And where the mobs should be, I see flashing/clipping of a few mobs. Only for split second at a time. So I can basically try to play bard songs in response to where I see the flashing/clipping mobs. Meanwhile this is during a 1-2 second delay in song response/ or if I consider something. I managed to kite down 112 mobs. But it was pretty risky with 6-8 second delay.
In The Overthere, I did a 100 mob kite with 1 second delay and had not just the mobs flashing/clipping, But also other players. the 100+ mobs in OT seem to be possible but only because of a lack of Caster Mobs.

I hope this helps.