Most likely we will simply report to the new Warchief. That particular quest isn't all that relevant to Garrosh anyway, since the reason you're reporting is that you know that you and the quest giver did wrong by resorting to fel magic which is forbidden (with some possible exceptions).
---------- Post added 2013-04-04 at 02:40 PM ----------
Indeed. Which is what I meant with that the level one character is sort of in its own dimension of the timeline, it's stuck in the past. Because the real present is the latest added content, right now 5.2, the forces of the Horde and Alliance are currently fighting the Mogu and their Thunder king, whilst the Sha has mostly been dealt with. Soon we will move on back to Azeroth and focus on how Pandaria has affected the old world (5.3).