I thought that this is interesting, and part of me wonders if the change isn't because there's a feeling that there are too many kids of ethnicities where rote memorization is perceived to be the norm back in the homeland. If you get my drift.
From the Los Angeles Times:
Spelling bee whiz kids must now must take vocabulary tests
To bee, or not to bee, has now become a tougher question to answer -- even for whiz kid spellers.
The full story can be viewed at: http://www.latimes.com/la-na-nn-spelling-bee-vocabulary-test-20130409,0,3384939.story?track=latiphoneapp