Up until now, any character who has been deleted has been erased completely, and permanently. Any progress would be erased, the inventory items cleared, and the name made available once more.
But, as I mentioned earlier, update 6.0.2 has come down from the heavens like a digital deus ex machina, and will give you the option to “undelete” your characters as well as preparing the game for Warlords of Draenor. Now, there are some limitations to this, which you can find detailed below.
– Characters under level 10 and Death Knights at level 55 are not eligible to be undeleted.
– Characters between level 10 and level 29 will no longer be recoverable after 90 days.
– Characters between level 30 and 49 will no longer be recoverable after 120 days.
– All other characters level 50 and above are eligible to be undeleted at any time.
The names of any deleted characters will also be bound to an account for a set period of time, giving players the chance to reassign or reuse the names if they so wish. The old name’s new owner must be renamed, transferred or deleted if the player wishes to restore the original character.
You can read the full patch notes here.