I think it was a bug that was fixed. The actual quest that had you fight like 6 tamers per continent was supposed to be a 1 time deal, but it was bugged and was a daily. they may have fixed the bug.
you can still do the daily for each continent ( winterspring, shadowmoon, outside Kara, Argent tourny) as daily quests, and you can still fight the other tamers in basically every zone.. but the quest that had you do the chain of tamers per continent is a one-shot quest, not a daily anymore.
This is just a guess, but I remember before 5.3 that a dev had said it was a bug that it was a daily.