Kaivax, a WoW forum community manager, revealed that WoW Classic's class design, battleground mechanics and stats on existing items will be set to their 1.12 state, despite the game releasing content that expands beyond that. This removes "progressive itemization," so if the stats on a specific piece of equipment was changed during the original updates, that won't take effect in this version.
":" - 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.
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.
The argument for this is simple: what makes classic WoW great to one player might be different from what makes it great for another. And who are Blizzard's designers to say which old features were just good or bad design for each player? It's an approach that shows Blizzard believes (at least to some degree) that WoW doesn't just belong to its creators but to its fans. That struggle between authorial intent or game design orthodoxy and "the player is always right" is at the heart of many of gaming's big contemporary controversies. But so far, Blizzard seems committed to its plan with regard to WoW Classic.