No, we have enough algorithmic sorting as it is. Sort by trending would only result in creating a massive echo chamber a-la-Reddit where short, snappy, uncontroversial comments rise to the top.
In my opinion, Hacker News would have been even better without the karma system. The only thing karma promotes is echo chamber thought, people playing it safe because they love the karma hit, and people playing the troll because they get off at seeing their comment greyed out.
That said, I can't fault pg for adding karma because in 2000-something when he wrote HN the Reddit model was seen as a fancy improvement over forums. Today we know karma systems just cause the signal-to-noise ratio to decrease massively as the user base grows, but is excellent for engagement metrics. I don't think pg wanted to optimise for engagement, but thoughtful discussion.