I think Discord-style emote reactions is a good idea; it's a nice way to non-intrusively weigh in when you want to acknowledge a post but don't really have anything to add to the discussion.
I don't think we need to bring back any form of karma system, though. They are mainly useful when you're dealing with post volumes that are too high for chronological order to be a reasonable sorting method and need to get some feedback from users about what should rise to the top and what should get buried, but with our current amount of posts I think it offers more downsides than advantages. Karma systems with downvotes don't provide helpful feedback (keep in mind a lot of our worst posters are probably kids that don't know better yet), and karma systems without downvotes generally means that, as long as enough people see it, even the most vile things you've ever read in your life will have several likes, which makes it look like the community agrees with those things, even if the reality is that the vast majority of people who saw the post would have downvoted it, and even if the comments reflect that, well, you're probably gonna see the likes before you see the comments.
I don't think we need to bring back any form of karma system, though. They are mainly useful when you're dealing with post volumes that are too high for chronological order to be a reasonable sorting method and need to get some feedback from users about what should rise to the top and what should get buried, but with our current amount of posts I think it offers more downsides than advantages. Karma systems with downvotes don't provide helpful feedback (keep in mind a lot of our worst posters are probably kids that don't know better yet), and karma systems without downvotes generally means that, as long as enough people see it, even the most vile things you've ever read in your life will have several likes, which makes it look like the community agrees with those things, even if the reality is that the vast majority of people who saw the post would have downvoted it, and even if the comments reflect that, well, you're probably gonna see the likes before you see the comments.