The English curriculum should consist of reading, writing, listening, and speaking, and for the most part, I think curricula designers to a fairly good job in incorporating all of these, although curricula do vary considerably. The three lacks I do see are in the history of our language, a neglect of grammar, and not enough emphasis on diversity.
What I never see included is the history of the English language, which I think is an important part of this discipline. In order to fully understand English literature and in order to communicate in it more fluently, it is helpful to know the origins of the language, how it got from the language of some Germanic tribes to its present state. It is a fascinating journey because the language has taken in words and ideas from all over the world, and when we study its history, we do so, too.
I also am concerned over a lack of focus on grammar in the curriculum, an emphasis that enriches our understanding of English and our ability to communicate in it. It appears that grammar is seldom addressed once one leaves elementary or middle school. This needs to be reinforced better, or even re-taught, in high school and even at the college level. English is supposed to be a discipline, and a lack of grammar knowledge makes it completely undisciplined!
Finally, there is still a lack of cultural diversity in the curriculum in many schools. We should certainly continue to read the classics of Western civilization, but we should also be reading literature from all over the world, another way of being open to different and new ideas that would create understanding and more empathy in all of us.
Teachers are expected to cover a great deal in English courses, and I realize that asking us to cover even more might seem burdensome to some, but I do think that these three facets of English are enriching, fascinating, and important.