Extremes are not Good

With anything really, but particularly language, extremes are not going to cut it.
Although I fully believe vocabulary and grammar are very important to learning a language there seems to be so much more to it.
Many describe language as being a living thing because it is used by living, adapting people who then transform their native languages to fit their mood, trend, and society. To teach language in a way that holds one aspect it over another is teaching already outdated information and only a portion of it. How can someone take this outdated information and use it when that person doesn't have all the pieces? Language is a combination of many things; it is vocabulary, grammar, accents, alphabets (characters), and culture.
Stating this now, I now add a 6th thing to what makes a good language teacher- teaching culture.
The point is, it's all about balance and exposing students to everything. Focusing so much on one thing and letting everything else fall to the wayside is like hosting a party and spending all your time making the most awesome playlist that won't have to touched for hours- what is everyone going to eat?