World of Warcraft is very old, by videogame standards. It was released in 2004. And about every two years, Blizzard releases a new expansion to update the game. Typically expansions don't really replace content, but it does displace it, and changes to mechanics and player abilities are indeed permanent and "retroactive". And in 2010, the Cataclysm expansion DID actually replace the old content from the release game.
Even though a modern server architecture is used, Classic servers won't have the same features that current World of Warcraft does. There won't be cross-realm servers or Looking For Raid and Dungeon Finder automatic party matchmaking. There are still a lot of questions about how the team will tackle it. This endeavor is being undertaken by an entirely separate team at Blizzard from the one working on World of Warcraft and its next expansion.
Nov 15 Managing your time and Classic So how are you guys thinking you're going to do it? I know when I played Vannila, I sunk so much time into it as I didn't have any responsibilites. Nowadays I work 24 on, 48 off (which is actually good, except for raid days) and have a wife. I figure a lot of you will be in the same boat. That may be a good thing as it can slow the pace a bit.Crupzz4 Nov 15