Completing the last part of the TK attunement chain does not grant you the “Champion of the Naaru” title as of prepatch.
Several comments from wowhead mentions that if you had the quest in your log prior to the release of prepatch you would get the title upon turning in the quest.
Aswell as this from wowpedia:
“This title is still obtainable in 3.0.2, but only to those who accepted/completed [Trial of the Naaru: Magtheridon] and [30R] [The Cudgel of Kar’desh] prior to the release of 3.0.2. The quests obtainable prior to 3.0.2 launch had a different ID number than the same quests after launch. Those who completed the earlier version receive the title.”
I had the quest sitting in my questlog for quite some time leading up to prepatch since I checked wowhead+wowpedia beforehand if the title would still be available. However I suspect that the 2 different quest IDs mentioned in wowpedia article got merged somehow, since I did the quest and turned it in on the day after prepatch launch. The addon “Attune” shows everything but the last quest being done which leads me to belive the quest IDs have been merged.