I think attention to
personality rather than
role creates original, interesting characters. Stock characters are never "stock" because of their personalities; they are stock because their personality has been subsumed as secondary to a conventional role in a story. Merely creating new roles and titles for characters, without attention to personality, just creates new type of stock characters; however, taking an old trope and infusing that character with a unique personality will create a unique character.
I also think there is not only no dichotomy between doing something new and creating with reference to what has been done before. Ultimately the measure of what makes good art good isn't its degree of uniqueness but rather its degree of truth. You can say the most unique thing in the world, but if it doesn't ring true, it is meaningless as art. And most of the great human truths have been touched upon in some way in fiction; making great, unique fiction consists in critically re-examining and synthesizing what has come before. While I agree that it is lazy and uncreative to write the same thing that has been done before without reflection, only a fool thinks he is so unique that he needs no reference to the past or common human experiences. That is like an infant trying to raise itself without parents.
Particularity AND universality are both essential aspects of solid characters.
And while there is a lot of cliche literature out there, both fantasy and mainstream, just because that is what most people will want to read, I think that there is also a very healthy bit of "unique" literature both past and present. I don't think a lack of uniqueness is exactly a pressing problem, in fantastic or realistic literature. "Genre fantasy" had a little decline post-LOTR and Star Wars into cliches, but I think GRRM, um, skewered that with some Valyerian steel

. But the fantasy and wierd fiction that came before was strikingly unique (Peake, Lovecraft, etc), as has been much of the fantasy to come afterwards (Mieville, Valente). And with literary fiction, while you will always have cliche crap like
Water for Elephants selling big time along side second rate, cookie cutter "literary" novels, there is a long history of incredibly unique fiction ranging from the great Russian novelists to Woolf to Faulkner and Updike and more modern writers like Toni Morrisson, Michael Chabon, Jennifer Egan, and Tea Obrecht.
I just don't think in the big scheme of things, there is such a lack of unique characters out there that this is a problem that needs a new solution.