This is, in my opinion, the largest change that WoW Classic will have over Vanilla, and it’s something that simply can’t be undone. Back in Vanilla, guilds were very secretive over strategies of how to correctly defeat a boss. Videos of boss kills were virtually non-existent,and strategies on how to itemize and play various classes and specs were hard to come by, especially for newer players. This, in addition to the unforgiving raid requirements and difficult content, lead to a lot of the player base never really getting to see a lot of the endgame content. Those that did rarely ever did so efficiently, and it wasn’t uncommon for the best guild on any given server to take months to complete a raid tier. There is absolutely no way that this happens in Classic. The raids in Vanilla are very much a solved system by now. Every raid, and every boss and trash pack inside, has been thoroughly strategized and talked about to death over the last 14 years. Rest assured even if you and your friends never played Vanilla, someone in your raid party will know exactly what to do on every boss, exactly when the trash packs are going to respawn, and exactly what buffs and gear to get to prepare. That certainly doesn’t mean thatClassic raiding will be a cakewalk, but it will be different than how the majority of people stumbled through the content.
I made some route changes to the Horde levels 43-44 sections.  I have swapped 44 Dustwallow Marsh with 44 Desolace (the entire sections). This allowed me to do Deadmire (at lvl 43 instead of 38) and then go stop at TB to turn in Deadmire + The Black Shield at the same time, then fly quickly to do the Desolace stuff.  Doing 44 Desolace is now mandatory because I think its faster with the new routes. This will also make the level 53 grind much shorter.  I think these were great changes.

“To fill our pool of beta and stress test participants, we’ll be choosing dedicated players who meet select criteria from both the WoW Classic beta opt-in and the standard Warcraft beta opt-in. Participants will also need to have an active subscription or active game time on their Battle.net Account. While opting-in to the beta is the primary way to make sure you’re in the running to join the test it doesn’t guarantee an invitation to the closed beta test. We may also consider additional factors such as how long a player has been subscribed to the game so that we have the right mix of players to ensure great feedback toward making WoW Classic the very best experience for the community.”
Only really to expand on Gráinne's comment as regards the 'collecting' and 'roster development' sections - which are, as said 'distinct' although they are intrinsically linked - I would like to point you in the direction of the in-game Achievements > Battle Pets > Collect tab. There are a series of achievements called Raiding With Leashes, pretty much all of which can be completed via the auction house - if you have the gold/inclination - or by completing old raids. 

Things like Tauren melee reach being bigger, which is something I experienced going away live during Black Temple Illidan progression (at least for that particular encounter), is confusing to players as it's a significant advantage over other races in some instances. No quest tracking is another apparently confusing issue, as many Mankirk's WIfe seekers well know, and there's a whole lot more where that came from:
“To fill our pool of beta and stress test participants, we’ll be choosing dedicated players who meet select criteria from both the WoW Classic beta opt-in and the standard Warcraft beta opt-in. Participants will also need to have an active subscription or active game time on their Battle.net Account. While opting-in to the beta is the primary way to make sure you’re in the running to join the test it doesn’t guarantee an invitation to the closed beta test. We may also consider additional factors such as how long a player has been subscribed to the game so that we have the right mix of players to ensure great feedback toward making WoW Classic the very best experience for the community.”
Now that you know to loot everything (see tip #1), you’ll have a lot of items in your bags. Any item that is white quality or greater may sell on the Auction House. How do you know what will sell well on the auction house? Trade goods and green quality (or better) items will almost always sell on the Auction House. See our Auction House guide (coming soon!) for more information.

World of Warcraft Classic is set to launch later this year on August 27. However, ahead of the fall release date, Blizzard is offering a WoW Classic beta sign up period, where players can get a taste of the game a bit early! The WoW Classic beta period is a time for the developers to test out their game and touch up any bugs before it releases worldwide. In exchange for getting early access, fans will be asked to report any bugs or issues they come across while playing. so that it can be polished up before launch. So, how do you sign up for the World of Warcraft Classic beta?
When it comes to Classic, Blizzard's goal is to provide an authentic Vanilla experience, but they also needed to come up with technology to handle many players at launch, which is similar to sharding. While the use of this technology will be limited to the first month following launch, many players are questioning this decision and wouldn't like to see layering in the game at all.
×