This Shadow Talent Build is the fastest for Leveling Up a Priest Class from 1-60 in WoW Classic patch 1.12. Spamming Shadow Damage DOTs while kite mobs will be the name of the game with this build, having the ability to sustain your health is just a bonus. You will just need to make sure you are stacking enough spirit so you don’t run out of mana often as that will slow down the levelling process drastically.
Through out the game, the quest log will be capped to 20 many times. The guide makes use of maximizing the total amount of quests you can accept at once. Because of this it is important to follow the guide exactly and only accept quests if the guide tells you to so you won't run into issues not being able to accept a quest. If you do accept a quest that is not listed in the guide, write it down because you may need to abandon it in order to keep following the guide if your quest log is full.
Blizz stated in a watercooler that they're using the 1.12 database as a starting point. I don't think it's a stretch for people to assume that most game features and mechanics will be in their 1.12 state. The kind of stuff I would expect to see reverted would be numerous AV changes, but I seriously doubt class mechanics are going to be reverted. I'd be surprised if the threat changes that ruin pre-naxx encounters are reverted.
Logging in for the first time, being welcomed by THAT login screen and THAT music... You can't not be taken back if you've played Vanilla, and especially if you've played 2 years of it non-stop all day every day. I probably stayed 10 minutes in character creation just because of the music alone (and trying to get my character looking exactly as it did back then - although I wasn't a shaman then). The whole intro experience was especially amazing for me since the Tauren starting zone was my first encounter with WoW in the EU beta, and a little bit of that spark did return. But is that all Classic has to offer? A trip back in time when we were wowed by the game for the very first time?
One thing they told me when I dabbled into computer science back at university was that 80% of the bugs only take 20% of your time to fix. That's why sometimes you see issues persisting for very long times, not because the devs are lazy or incompetent, but because there is usually a priority list of problems, with the severe-but-easy-to-fix ones always taking precedent and the not-game-breaking-but-difficult-to-solve problems being last line.
Why Skinning? Skinning is incredibly easy to level up while you are leveling your character. The leather that you skin will almost always sell on the Auction House (albeit not for much, but hey– it’s free gold!). Even if you don’t want to take the effort to sell the skins on the Auction House, you can simply vendor them for a significant amount of extra gold.
I recreated my very first character -- a human warrior, because in the last-push alpha test I joined in 2004, there was no Horde -- and logged in. Immediately, I was surprised by how good the graphics actually looked, for being 15 year old textures-on-polygons. Warcraft's bright colors and cartoony aesthetic continue to this day, so all the increased resolution and better-contoured characters in Lordaeron don't really change the game's visual aesthetic.