Kaivax, a WoW forum community manager, revealed that WoW Classic's class design, battleground mechanics and stats on existing items will be set to their 1.12 state, despite the game releasing content that expands beyond that. This removes "progressive itemization," so if the stats on a specific piece of equipment was changed during the original updates, that won't take effect in this version.
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].
Before we give you the Classic WoW Best Leveling Class, let’s discuss what we consider to be the Best Classes to choose for levelling. These are ranked based on how fast and easy it is to level up from 1 – 60 whether you are doing it with a group or simply Solo levelling yourself. Classes with AOE Damage and the ability to self heal tend to rank higher simply because it’s much easier to level up when you can sustain your health and clear mobs of monsters. In the case of Warlock and Hunter Class you have a pet that can help tank mobs while you DPS them down, this is another huge benefit when leveling up.