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:
Beginning May 15, select WoW players will be invited to participate in a small-scale, focused closed beta test. Players will also get a chance to help put our servers and technology through their paces in a series of stress tests running from May through July—you can opt in now through Account Management and select the WoW Classic beta. Subsequent stress tests will extend the opportunity to even more players. Level caps will also be in place to ensure we’re emphasizing the “stress” in “stress test”
The original World of Warcraft was released in 2004, and World of Warcraft Classic aims to recreate the state of the MMORPG before its first expansion, The Burning Crusade, was rolled out in January 2007. Previously, players looking for a “vanilla” version of the game were only able to experience it on custom servers such as Nostalrius, which Blizzard shut down in 2016 to protect its intellectual property.