As someone who's leveled enough Alliance and Horde characters to fill multiple accounts, it remains to be seen whether replaying content I've seen many times before will keep my attention in the long term. But even the thought that it might suggests that for many people, this could represent a novel experience compared to the modern game, something at least worth a try.
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.

15 Nov Regeneration on classic demo Hey I haven't seen any discussion about this yet, but wasn't the regeneration on the demo a bit much? From watching streams and videos from different content creators it seem they were regenerating health and mana way faster than I remember and definitely faster compared to vanilla servers. What's your opinions on this, oh wise forum debaters?Eaqe2F22511 15 Nov

While our initial effort helped us determine the experience we wanted to provide, this second prototype really defined how we’d get there. Starting from a modern architecture—with all its security and stability changes—means the team’s efforts can be focused on pursuing an authentic classic experience. Any differences in behavior between our development builds and the patch 1.12 reference can be systematically cataloged and corrected, while still operating from a foundation that’s stable and secure.
Gold in World of Warcraft: Classic can be earned with a bit of luck too. By killing and looting mobs you might find some truly rare items. Some of them might be usable by you but others might not. Don’t just sell that piece of rare equipment to the nearest vendor as it can earn you quite a bit in the auction house. Especially if it’s an item for a level 50+ character.
14 Nov Will I gimp my raid by playing Shadow Priest? I have a burning passion for shadow priest in vanilla and I mostly want to raid. I've been talking to some people I know and some of them say that they would never bring a shadow priest into raid and others say that they absolutely want 1 shadow priest in their raid group. Why the mixed reactions? From my understanding, shadow priests in classic are mainly brought to raids to buff the damage output of your warlocks with Shadow Weaving. How many warlocks would a raid need to make 1 shadow priest worth bringing over a mage for example, and am I gimping the raids DPS by taking up that raid spot?Luminé39 14 Nov
The primary goal of Conflict and Strife is to provide an interesting choice in PvP by allowing access to an extra PvP Talent. It’s not necessarily going to be a strong option for PvE. The acquisition of this Essence is via PvP, and is totally optional for PvE-focused players. While there may be interesting PvE uses for some of the choices, it is not expected to be a strong competitor on usual PvE criteria (like total throughput) on every spec.
Making "new" guides seems kinda out of place. Not only is there still alot of information from back then available, there came alot of information up for minmaxing available for both leveling and raiding, ontop of various bis gear lists that cover patch progression aswell if necessary. Wether people like or dislike pservers does not make the various information found on their forums less valuable. 

14 Nov WoW Classic BlizzCon Demo Pre-Download Hi everyone! We’re incredibly excited for you all to get your hands on the WoW Classic BlizzCon demo next week, and to help make things as smooth as possible, we’re making the client available to download for Virtual Ticket holders starting today. Over the next 24 hours, we’ll be enabling the ability to download the WoW Classic demo through the app for players who have purchased the BlizzCon Virtual Ticket, as well as standard BlizzCon ticket holders who have added their Virtual Goodies code to their account. If you don’t see the option to install the demo right away, don’t worry – you’ll still have plenty of time to download the client before the demo goes live during BlizzCon next week. We can’t wait for you to get a peek at what we’ve been working on, and hope you enjoy this preview of what’s to come!Lore53 14 Nov
The notion of ongoing updates as they originally appeared, though, raises the question of expansions. Blizzard has released seven expansions in all. And while later ones like Legion or Battle for Azeroth would feel out-of-place within the Classic framework, it stands to reason that some players may want to experience earlier expansions--such as The Burning Crusade or Wrath of the Lich King--in the context of World of Warcraft Classic. Blizzard isn't committing to this, but also hasn't ruled it out. 

Arms: Sharpen Blade - When activated, your next Mortal Strike will deal 15% increased damage and reduce healing taken by 50% for 6 sec. Fury: Battle Trance - You go into a trance causing you to regenerate 3% of your health and generate 5 Rage every 3 sec for 18 sec after using Raging Blow twice in a row on a target. Using Raging Blow on a new target will cancel this effect. Protection: Thunderstruck - Thunder Clap roots all targets for 1 sec. Tuning

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.

Note: My goal here was to create a comprehensive list of everything you'd need in order to learn to play any class (from Level 1 to Naxxramas)—meaning I am only including class-specific resources here (so no profession guides, general leveling guides, etc). Teeb's Resource list is much broader in scope, and I highly recommend you take advantage of it (as it contains a plethora of non-class specific resources as well). If you're not aware, Teeb is also responsible for the Race & Class Comparison Tool, Dungeon Tier Sets Gallery, and a huge variety of other insanely useful resources.
 ":"  -  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.
“By the way, one of these codebases [Vanilla WoW] is extremely buggy, and we had already solved a lot of those [bugs]. But we can’t solve them [this time around] because... ‘reasons’ if we’re thinking about the Classic timeline. And so we really struggled with it for a very long time, and one of the things that we talked about when we were discussing different ways to do it was to do what’s called a ‘fork.’ So we did a fork of our existing modern server stack and then reimplemented the systems that we needed to support Classic WoW. And made sure that the tuning was right and imported the old data, we had the old code and a way to compare. Having the backend tools, and the backend server, and the modern hardware was a requirement to realize this project.” Essentially, what the team did, was teach modern WoW to speak old Classic data. 

So committed, in fact, that modern WoW players are trying the beta and reporting what seem like bugs today but what were actually intended functionality 13 years ago. This became such a common occurrence that Blizzard publicly posted a list of known non-issues called the "WoW Classic 'Not a Bug' List." For example, hitboxes for the Tauren player race are much larger than those of other races. In a modern game, this would be seen as a serious balance issue (see: Apex Legends). But it's what vanilla WoW was like, so it has been faithfully reproduced.

Some players choose to take a slightly alternative approach to their gold farming. This approach can take an extensive amount of time and dedication. Many people choose to train a ton of alts, solely for the purpose of making money and multi-tasking. In World of Warcraft Classic, professions are usually paired together. For example, if you’re training alchemy, you will need herbs to create consumables (e.g. flasks) that are used for raiding. An intelligent and observant player could seize this knowledge by creating one alchemy alt and one herbalism alt, swapping items as needed between each other. This fully mitigates the fees by the Auction House, which means your profit is maximised. Another complimentary combination you can use is skinning and tailoring, or cooking and fishing.