Just finished reading on the stemgeeks site :)
I think this is a good starting point. Including only the posts that have earned support from the community account is a good filter.
A while back, I toyed with discounting comments shorter than 20 or so characters but decided against it in the end. Instead I occasionally check for people repeating the same short (or longer) phrase, and actually, there is very little of that.
Good luck :)
I tried without the filter, and indeed we see a few permutations in the ranking, but no large change (in particular as we have the blacklist with the bots).
I am still thinking about what to do with the sqrt metric, that is possibly not ideal. But for now, I have no clue.
PS: the post can also be read on the STEMsocial app. ;)
I think you'll have to try it and see, there's no harm in adjusting metrics in the future.