It is well worth noting players will face a choice with their present characters from lolgaroket's blog

It's well worth noting players will face a choice with their present characters: All current WoW Classic nation-states are WOW Classic Gold set to switch to Burning Crusade-content "Progression" nation-states in Burning Crusade Classic, so gamers will need to determine whether or not to mechanically transition to this sort of or to deliberately migrate to new "Era" nation-states, in which content material will stay confined to Shadow of the Necropolis on Azeroth. Additionally, sooner or later soon, the game consumer will be updated so that draenei and blood elf characters can attain degrees as excessive as 60 before the expansion debuts.

While attunement chains will exist in Classic TBC, Blizzard developers stated the attunement quests might be nerfed in a few capacity to house for the phase-fashion release of instances with a view to mmobc.com  fluctuate from the unique TBC.