100% Achievement completion now possible after the Coiling Fate fix in patch 2.0.5!
Reaching 300 paragon was definitely a hell of a grind.
That's all achievements done, and only missing the feat of strength for 6 million goblin kills. Which doesn't count. Because that achievement was clearly created by someone who failed basic math in grade school.
Even after a full season of playing and reaching 300 paragon - a paltry 200 goblin kills.
For reference, even if you somehow managed to kill 200 goblins every single day, it would still take you over 90 YEARS to complete this achievement.
So yeah, those player title rewards might as well not exist.