Great article on the value of vocabulary:
http://www.motherjones.com/kevin-drum/2013/01/building-better-kids-vocabulary-edition
It is beyond me how anybody could doubt the importance of vocabulary, unless you have the agenda of keeping those that don't "need" a strong vocabulary disenfranchised.
I'm also growing tired of the discussion whether words have to be taught in context (works to a degree for students who are at the right level to figure out the text with a few missing words, but costs a lot of time and energy) or through explicit instruction. Of course there are terribly dull and useless ways of "drilling" words, but using internet technology, explicit instruction and review can be very effective and smart, like with our LearnThatWord.org program. For a student who is thousands of words behind upon entering school, explicit instruction is the only lifeline there is.
Unfortunately, although we offer free coaching through Vocabulary Junction, many are not that lucky.