I suspect that there are masses of people who are compelled by hypergraphia and ramble on with no particular talent for communication or for enlightening others through their writing. You are not one of those people. Your writing is highly literate, interesting, and I learn from it. i.e.: You posses the marks of a talented writer.
Therefore, it's difficult for me to label your urge to write as a problem.

I used to write quite a lot when I was younger, including writing poetry, some of which was published in reputable journals.

I don't write nearly as much now, probably because I do most of my writing online, communicating with others. I do, however, have a life-long and ongoing "burn" to create, to be creative. Being creative manifests in a variety of ways. I do believe that the extremely passionate urge to create is an aspect of hyper-mania and mania, but I don't care - creating is essential to me; it's my life's blood.

Is your hypergraphia disturbing you lately?