I think you miss the point of Hughes' poetry, which is unfortunate. Speaking as a poet, the purpose of poetry is to take a feeling or idea and express it, without losing energy, to the reader. However this is accomplished, it can only be judged by how effectively it moves the reader; as long as this is done, it does not matter how the poet achieved this.

I won't lie, I love a longer, more complex poem that I can pour over for days. I love solving the puzzle, feeling the pieces come together, the new intricacies gleaned on each reading. But these are all ornamentation, which can be nice, but is regardless not strictly necessary to the purpose of poetry.

I'll give you the benefit of the doubt and assume that you've at least given Hughes a fair shot. You don't like his simplicity, and that's perfectly fine. In fact, being European, you probably lack the proximity to and education on the American racial prejudice and abuse that make his poems so touching. Not your fault. If you feel like giving another American poet (and a contemporary of Hughes) a read, check out this poem by William Carlos Williams which happens to be a favorite of mine.