My problem with Timeless Isle is that even if I go there, and kill stuff, I just can't feel myself progressing in any of my "goals" there. On my main, I grinded the Bigger Bag achieve. I am currently on 170-180 ish kill on the Brew alemental and Gu'chi, yet no pet. Grew tired of it and abandoned the isle completely after it.
Got one of the mentioned pets on alt on the first kill, and it doesn't count. On main I don't need gear, on alts I don't "dare" to kill rares because if something drops from the GNBB list, it doesn't count. Besides, on alts, I don't seem to be getting those Burdens (and if I get one, it will 80% turn into some terrible itemized gear), on main I sneeze on something and I get a Burden.
It is an illusion. Illusion of doing something useful, and illusion of progressing, illusion of content.