At BlizzConline, it was announced that the original World of Warcraft's first expansion pack would be coming to World of Warcraft: Classic. The expansion is known as Burning Crusade, which took players into the realm of Outland to continue their adventures. World of Warcraft: Burning Crusade Classic will deliver a similar experience for players who want to relive their MMORPG memories from 2007, though it'll be a one-way street if they choose to travel to Outland.
In an upcoming pre-expansion patch, players will be presented with a choice. They can either take their WoW: Classic characters to Outland in Burning Crusade Classic or have them remain in Azeroth. If players choose not to participate in Burning Crusade Classic, their characters will be ported over to the new "Classic Era" servers, which will feature content identical to how WoW Classic is right now, before Burning Crusade Classic is added.
The reason players will need to pick between these two options comes down to Burning Crusade Classic utilizing a different client than WoW Classic. A player's characters will appear in both clients until they select them, in which they'll be asked to pick between the Classic Era servers or the Burning Crusade Classic servers. Once the choice is made, players will be forced to use that character on whatever server type they selected.
If players want to use the same character in both the Classic Era servers and Burning Crusade Classic, they'll have to use an optional paid service to clone their character. This means that players will have two different versions of the same character, allowing them to play both pre-Burning Crusade WoW and post-Burning Crusade WoW. Choosing between Burning Crusade and classic World of Warcraft is actually a pretty significant decision, so players may be incentivized to clone their characters.
Burning Crusade made a lot of significant changes to the classic World of Warcraft. It raised the level cap to 70 and introduced new abilities for characters to learn. It also added two new classes with the Paladin and the Shaman and two new races, the blood elves and the draenei. However, the biggest change between WoW Classic and Burning Crusade Classic is the removal of spell batching.
Spell batching was an exploit that existed in the original WoW. Spellcasting classes could take advantage of the long delays in the game's server processing time to create some interesting interactions between spells, such as classes with self-harming abilities being able to cancel out other spells. These kinds of interactions happened because the game server would process the actions together in batches, thus prioritizing certain spells and abilities over others.
Spell batching was recreated for WoW Classic due to how integral the exploit was for PvP combat. However, as outlined in Blizzard's Burning Crusade deep-dive, spell batching ended up causing many issues with balance and stability, with more bugs being created because of its existence. As such, the mechanic will not be recreated in Burning Crusade but will remain in WoW Classic for the foreseeable future.
The removal of spell batching is a good example of why some players may want to stick with the Classic Era servers when the time comes to choose. However, for those who want to relive WoW's first-ever expansion, Burning Crusade Classic looks to be just that. The exact release date is currently unknown, but Blizzard has confirmed that it'll happen sometime this year, after a beta test run.