However, that’s not the full extent of Blizzard’s announcement. The developer behind World of Warcraft Classic has also announced that it will release a closed beta test for chosen (note this word) players to participate in. The closed beta is meant to test Blizzard’s servers, which I’m guessing will be pretty full once the game actually releases. Blizzard hopes that this beta can prepare them for a smooth launch, since this is pretty big for World of Warcraft players.

Swim Speed Potions (used especially at lvl 37 for Faldir's Cove in Arathi Highlands and lvl 57 in WPL).  Try to get multiple stacks of these.  I also recommend keeping a stack of these always in your bags.  You will frequently pass rivers and lakes and can use these potions to pass them faster through out the guide.  Please note that these potions do not stack with Druid's Aquatic Form and Glyph of Aquatic Form.
Within the context of Classic, the method most frequently proposed is to re-tune bosses to make them harder. Rather than copying the numbers, re-create the relative difficulty. Kind of like, when you first start working out, you use small weights. When you get stronger, you lift bigger weights. The WoW community is more knowledgeable, more experienced, has better hardware, etc. We're "stronger." So give us tougher bosses. There are a lot of forms that could take. Bosses were constantly re-tuned during vanilla anyway, so if Ragnaros does 10% more damage or something, is that really a problem? I don't think it is. What about resistance gear? back in the day, collecting resist gear was a thing people did. But the numbers and strategies are so well known today that only the tank really needs it anymore. Bosses could be re-tuned with more resistible elemental damage so that's important for entire raids to gear appropriately. That would be entirely keeping with the spirit of vanilla even if the actually numbers sitting in a database somewhere were different than they were ~13 years ago. If you want to go a little farther, a few people have proposed adding new abilities to old bosses, adjusting their timing, etc.
I think you are referring to the Env Bert strat I have linked. Basically I agree. But you might have noticed that I already had added min power to pet #2, in order to exclude some of the substitutes. Though, I didn’t wan’t to do the same with the Blazehaound (pet #1), because I think the strat is doable also with a suboptimal breed. But maybe you are right and I should just exclude any non-P/P breeds.
The Horde levels 50-60 guide has been rewritten and revamped.  My 1-60 Horde leveling guide is now completely updated for the 1.12 Drums of War patch.  As you can see it is about 15% larger than the 40-50 guide (single largest guide page yet).  There is also a lot of route changes.  I moved the entire Silithus section from level 55 to level 58, which allowed me to include a lot more quests for that zone.  There is also a lot of other improvement to the route, including adding a lot more quests into the guide, mostly from Moonglade, Silithus and Eastern Plaguelands.  This will make the final level 59 grind much shorter.

If a companion dies during the battle, it will need to be resurrected before it can participate in another encounter or be summoned as a traveling companion. Get that pet a medic! Or in this case, a Stable Master. Stable Master NPCs can heal and revive your pets for a small fee, and there is no cooldown on the Stable Master's heal. You’ll find Stable Masters in major towns and cities across Azeroth.

Occasionally it's also been proposed to re-randomize all the gear. We didn't have best in slot lists back then. People weren't starting out as a fresh level 1 character with a complete list of which dungeons to run at 60 in order to gear as quickly and efficiently as possible. Now, all that data is available. If gear were re-randomized then all of those lists would become useless and thing would be close to how they were. Which is a more important part of the "vanilla experience?" the fact that item X from boss Y has exactly Z stats on it, or the voyage of discovery? Personally I think that voyage is way more important. Do you remember how many points of which stat on the ring or whatever that Darkmaster Gandling drops? I don't. Would it kill your experience if the BiS for every class were in a different dungeon so people had to actually play to figure it out rather than simply consult a spreadsheet? I don't think it would. For that matter, it probably wouldn't be a bad idea to handle it intelligently so that the better gear is in later dungeons. I remember there because some weird cases where level 40ish gear was better than anything that dropped in level 60 dungeons.