See, this is what I don't get about these characters-only claims. Essentially these characters and what they do is now tied into the mythology, so the rest of the mythology becomes important by extension.
Fan point of view is a big part of it. For instance, who built the ruins on the island? To some fans, the question hasn't been answered at all, to others it has. To some, it's enough to know that the ancient peoples have been coming to the island for centuries and obviously saw the island as a divine place. To other fans, no answer could be thorough enough. The thing you have to ask yourself is what, realistically, can our characters actually learn the answers themselves in a believeable way? Are they going to stop trying to survive or fleeing the smoke monster to go on an archeological dig or translate hieroglyphs? Of course not.
The island has meant something different to all the different peoples who discovered it. That's all I really need to know. The show to me isn't about what makes the island apparently magical, it's how do we as human beings react to that? Do we consider it divine and build monuments and temples like the ancient builders? Do we think of it as a place of scientific possibilities like the Dharma initiative? Do we see it as simply an island to exploit for military purposes as the U. S. military did in the 1950s? Do we see it as an affirmation of faith in a higher purpose, as John Locke did? Or do we see it as a direct attack on our sense of free will as Jack did?
Those questions are much more interesting to me than "Where did all the hairbrushes go?"
Just my two cents.
Combine that with the show presenting itself as mythology driven and it's clear that there needs to be a balanced focus on both. Where that balance lies becomes the most difficult part to achieve.
The show has never been "mythology driven." Hell, for the first three seasons, half of every single episode is nothing but
a character study of a single main character.