He wrote in a highly idiosyncratic, era and incident specific style. When his current population of admirers has passed on, he will be read and studied by just a few obscure specialists at the college and university level. Even then, he will be cited in footnotes with greater far frequency than as main text. In the year 2040 and possibly much sooner, "Who was Hunter S. Thompson?" will be the Jeopardy answer that no one will know.Everything you say about his style could also have been said about Hemingway (who also killed himself).
-Eric
Many of his short stories are exquisite and timeless. "Big Two-Hearted River" and "The Snows of Kilimanjaro," to cite just two examples, are bereft of tedious topical and political content and are equal to anything that Yeats, Joyce, or Dostoevsky wrote. They are great art that can be enjoyed as great art for the great care that Hemingway invested in them.
Thompson was a manic, self-indulgent, incautious scribbler who could write some very funny and startlingly original lines. But even at his best he didn't approach the minor genius of, say, Ring Lardner.
That's my opinion, of course.