Because the karma is numeric, those buttons should all also have numeric values +1 (want more of this) or −1 (want less of this). It would be probably good to preserve the old-style “upvote” and “downvote” for people who just want to vote and not analyze why exactly they felt this way (because having to analyze everything would be a trivial obstacle to voting).
So perhaps the good mechanism would be to first show the choice of downvote and upvote, and after the vote is made, display relevant subcategories and let voter optionally choose one of them which fits most.
Then the total score of the comment should also display a most frequent flag or two. Such as “5 points, interesting”, or “-10, trolling”. Maybe display the flag only if overwhelming majority of voters agree on it; otherwise just numerical value without flag.
Because the karma is numeric, those buttons should all also have numeric values +1 (want more of this) or −1 (want less of this). It would be probably good to preserve the old-style “upvote” and “downvote” for people who just want to vote and not analyze why exactly they felt this way (because having to analyze everything would be a trivial obstacle to voting).
So perhaps the good mechanism would be to first show the choice of downvote and upvote, and after the vote is made, display relevant subcategories and let voter optionally choose one of them which fits most.
Upvote—nice, interesting, informative...
Downvote—trivial, wrong, off-topic, flamebait, trolling...
Then the total score of the comment should also display a most frequent flag or two. Such as “5 points, interesting”, or “-10, trolling”. Maybe display the flag only if overwhelming majority of voters agree on it; otherwise just numerical value without flag.