@The_Child: Allow me to offer my answer.
Your first question; my answer is NO. Before you can categorize a literature as "vague" or ambiguous, you need to interpret it in the first place. No direct knowledge is available to determine the ambiguity of a literary piece, we need to understand the intent of its author and many other things.
Your second question; my answer is NO. Hermeneutic standard says that in every objective portion, there is always a subjective part considering that only the letters have had access on the objectivity of terms while the intent of the writer remains subjective.
Your third question; the study of hermeneutics include the study of literary forensics and investigations. It means that when some literary claims are dubious, the more we need the science of interpretation which we call "hermeneutics".
Your fourth question; objective, clear and ambiguous are adjectives that require extensive hermeneutic studies. It mean that in the hermeneutic standards we cannot directly label a particular language or presentation without dissecting those employing the proper and reliable hermeneutic standards. What is proper standard? It depends on what subject category in which a literature may be classified. Example, in law - legal hermeneutics, in medicine - medical hermeneutics, in sociology - social hermeneutics, in science - scientific hermeneutics, etc....
Your fifth question; Yes, hermeneutics could also be used for the purpose of destruction, deconstruction, criticism, defend, justify, etc... THIS SHOWS how useful is hermeneutics in the world governed by language.
Your sixth question; Hermeneutics is absolutely useful in many ways. Did I use Schleiermacher's standard? No, I only use it when the subject is "intent of the 'inspired' writings".