more pointedly, comment sentiment is a naive and misleading signal of either submission or discussion quality. most simply because it's a poor proxy for why, but also because quality is an amorphous concept that defies direct rationalization (i.e., being numericalized), among other factors.
naive heuristics are also gamed more easily, especially because they have a tenous relationship to the desired signal in the first place.
slightly more interesting would be absolute value of comment sentiment, which would be a (still naive) measure of controversy/engagement. to really get at quality and value, you'd have to consider comment semiotics/semantics (the symbolic meaning and content), which complicates the effort exponentially (perhaps impossibly so).
naive heuristics are also gamed more easily, especially because they have a tenous relationship to the desired signal in the first place.
slightly more interesting would be absolute value of comment sentiment, which would be a (still naive) measure of controversy/engagement. to really get at quality and value, you'd have to consider comment semiotics/semantics (the symbolic meaning and content), which complicates the effort exponentially (perhaps impossibly so).