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.
A lot has happened in World of Warcraft in the fifteen years since it originally launched, and over that time we’ve come to expect certain things, not just in WoW, but in games in general. As players explore Azeroth as it existed back in 2006 during the WoW Classic beta, they’re reporting bugs – but in many cases, these ‘bugs’ are really just features that are working as intended. 
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