Given the subjective nature of this question, not all readers will agree with the following characterization of Reverend Gail Hightower (William Faulkner's Light in August).
Although Hightower fails at marriage (his wife commits suicide because Hightower fails to accommodate her needs as a wife) and being a minister (removal of his position in the church because of the scandal with his wife), he does prove to be resilient. Hightower proves he can withstand much criticism and failure (removal from the church, rumors from the people around him, and the tragedies which have plagued his life) given his ability to stand strong. Refusing to move from Jefferson, Hightower (initially) becomes an introvert (self-absorbed and isolated). Provoked by Byron Bunch to rejoin the "world," his involvement with Lena Grove (a constant optimist) allows him to emerge from his self-exile. HIs trials and tribulations have allowed him to possess the characteristics needed to "come out on the other side" stronger, wiser, and more confidant.
Based upon his ability to survive, I would not consider Hightower a failure of the text. Instead, his ability to survive (even with the extreme challenges) proves his worth and success as a character.