For classes who rely on energy regeneration such as Rogues, things have also changed significantly since the classic era. Regeneration used to occur in chunks based on the server “heartbeat.” So, to gain 20 energy, it would take a full two seconds. Today, the system is smoothed out so that that 1 energy regenerates every tenth of a second. This difference changed the timing of being able to use certain abilities. What seems like a minor convenience today actually changes the very flow of combat rotations and burst capabilities in classic gameplay. We felt this was important to restore to provide this authentic experience.
Nov 15 Classic Box Cost Disappointed in the decision to bundle the subs and (at least for now) not have a separate Classic sub option. That said, can we at least get a separate box cost for access to classic? It would: - help alleviate temporary bloat and subsequent dead realms - servers would be more stable population-wise over time - remove the bulk of the need for sharding - give a solid idea of how many servers will be needed - allow blizzard to set up a separate classic forum for those with a monetary commitment - with a separate forum group, feedback would be limited to those with a vested interest The subs would still be bundled, but there would be a box cost, akin to what one would have to pay for BFA access. A very good to-the-point post from later on in this thread:... Another good post about how the current setup would necessitate sharding:... A decent (albeit short-term) alternative:...Brokenwind314 Nov 15
In the past, if someone accidentally looted something they didn’t mean to in a group, players would have to contact customer support to trade it. In the modern system, players are given a period of time in which they can still exchange loot with others. This is a convenience we felt was worth retaining for Classic rather than making people go through customer support. (Sorry ninja looters!)

The first—and among the most important—decision we had to make was which version of the game to focus on. As many of you have noted, the classic period was two years long and full of changes. Core features like Battlegrounds were introduced in patches after WoW’s original launch, and class design similarly changed over time. After careful consideration, we decided on Patch 1.12: Drums of War as our foundation, because it represents the most complete version of the classic experience.

Even though the guide was developed with a hunter, the guide can be followed by any class.  Except you have to do your class's quests which aren't a whole lot.  I do have full intention to make my guide friendly with all classes in the future by listing all of their steps as well.  There will be a toggle that allows you to show which class's steps you want to see in the guide.  But this is coming later.
Nov 15 The most hardcore thing you can do. In vanilla? I have a few things that could be it. Playing on a perma death PvP server and kill kel'thuzad. Without dying even once. Being able to kill a mage/rogue/warlock/pally in all BiS gear Soloing a high end dungeon boss like rivendare or dark master gandling. Leveling to 60 with no gear or weapons or pet of any kind. That is by far the most hardcore, life threatening thing you can do in vanilla wowHavell7 Nov 15