The Brawler title is now permanent.
WHAT TITLE, How do I get this!?
Think you get it from killing the rare bosses.
Google "brawler title"
http://us.battle.net/wow/en/forum/topic/7199964593
That seems to be the most up to date information on it. The next two results are a wowhead link to the title with the same things as the official forums and then your thread.
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