The vanilla WoW Horde leveling guide you see on this site was originally made back in 2006 by Joana (AKA Mancow, or FuriousPaul). The guides have been tweaked many times over the years to make things "faster". The leveling guides were made because of all the messages I got from people asking me how I was able to level up so quickly on new realms. I was first to level 60 on 7 different realms (3 with Mancow and 4 with Joana), even winning Blizzard's "First to Level 50" contest they held back in 2006.
The Horde levels 50-60 guide has been rewritten and revamped. My 1-60 Horde leveling guide is now completely updated for the 1.12 Drums of War patch. As you can see it is about 15% larger than the 40-50 guide (single largest guide page yet). There is also a lot of route changes. I moved the entire Silithus section from level 55 to level 58, which allowed me to include a lot more quests for that zone. There is also a lot of other improvement to the route, including adding a lot more quests into the guide, mostly from Moonglade, Silithus and Eastern Plaguelands. This will make the final level 59 grind much shorter.
When it comes to levelling the Priest Class from 1-60 fast, XP grinding locations is only half the battle. You will need to make sure your weapon does enough DPS so that you can clear these mobs fast enough, it should also be noted that monster should be around your level to make sure to gain the 100% XP Reward. The Level your character should be before you start that specific location will be indicated to left in a Blue Color for Alliance [Lvl 35-39] and the Orange Color for Horde [Lvl 35-39]. The Mobs you are looking for in that specific area names are Bolded [Mob Name].
":" - Any time a step ends in a ":" instead of a "." means that the next step is part of the current step you are on. This generally means the next step should be done while working on the current step. This means every "start working on" or "continue working on" will end in a ":". But this is used with other occasions as well, so keep this in mind.
The argument for this is simple: what makes classic WoW great to one player might be different from what makes it great for another. And who are Blizzard's designers to say which old features were just good or bad design for each player? It's an approach that shows Blizzard believes (at least to some degree) that WoW doesn't just belong to its creators but to its fans. That struggle between authorial intent or game design orthodoxy and "the player is always right" is at the heart of many of gaming's big contemporary controversies. But so far, Blizzard seems committed to its plan with regard to WoW Classic.