Reputation systems, "engagement" vs. participation, and the "first post!" effect

I'm mostly very appreciative of everything @Deimos has accomplished here; so far, it's been a very smooth and interesting alpha experience. I'm seeking some clarity on how the eventual reputation and trust system he proposes might eventually materialize, and would like to start a discussion among other users as to what mechanic they're seeking. [My apologies if this has been addressed previously - search functions are also anxiously awaited.]

There are multiple social sites (Slashdot, HN, Reddit, etc.) which use new/active/upvoted categorization for ranking front-page comments. This seems to be reproduced here, and generally, I don't have a problem with it as long as the permitted posts don't become just a reproduction of inflammatory click-bait available elsewhere, dank memes, etc.

However, on a per-user-basis, the first reasonably-well composed comment on a thread collects most of the votes. My observation is that in an active post thread, the best-reasoned/researched posts may occur after dozens/hundreds of comments, as people who don't spend their entire lives camping on a social site (highly-engaged!) join, read through prior material, and comment. These users don't garner the votes and reputation points which highly-engaged users might, even though they're working harder as quality participants. Threads die, potentially prematurely, because there's no reward for late arrivals or continuing disputation.

While this phenomenon hasn't become egregiously manifest on Tildes yet, there's certainly potential for it to arise. Would it make sense to age out the votes on the "first post!" comment, so that there's some encouragement for deeper or longer posts to continue on an active thread?

Since Tildes is ostensibly built to discourage the "engagement" tactics required to optimize for maximum ad views (e.g. https://www.bitcatcha.com/blog/instagram-tools-strategies-no-ones-talking/), is there another system which might further encourage participants to engage in thoughtful discussion and high-quality posts instead?