I guess maybe I'm familiar enough with it to just slam it out. I don't recall any low droprate quests as bad as 5%. Although Blizzard has been screwing with stuff lately. Do you remember which quest it was? A lot of those can be skipped if they're too tedious. Like literally ALL the quests on that little island in the NE corner of the map with the ghost pirates underwater and the dragon whelps.
I've identified a pesky bug that had me confused for months now. I would get serious slowdowns (from 60fps to as low as 20fps) whenever the dugi waypoint arrow was active and I started moving across the map (especially quickly like flying on mounts/flying masters etc.). I tried everything, and all that could fix it was clicking "Remove all waypoints", so that the arrow turned off. I thought maybe the arrow needed to constantly update locations/routes, and a new game update had perhaps broken that feature a bit.
We’ve spent a lot of space giving advice for those with less experience in the nuances of World of Warcraft. If you’re a player who generally knows how to get around the game—or did at one point—you’re probably still going to feel a little stuck if it’s been a decent amount of time since you last played. For example, why does your favorite weapon no longer work the way it used to? What’s the latest currency you have to know about? Should you ever waste time hanging out in your Garrison again?

One of the very cool things about Zygor’s Guide is that it’s automated. Not only do you not have to manually switch from game to guide, you won’t even have to click to the next quest. Complete a quest and the guide will automatically update to the next quest. The guide does it for you (usually, sometimes you’ll have to click to the next quest on your own.) It really is like having someone giving advice over your shoulder. Here’s the next quest, here’s what you need to get…
DoTs: Assuming that the mob is going to live for certain periods of time, it is worth it to place DoTs up. If the mob lives for at least five seconds, cast Pain. If it lives at least seven seconds, cast VT. The ideal time to cast DoTs is when it would be replacing Flay, but you can substitute Blast if the mob will live longer. Make sure to cast Bolt on cd though!