I’d prefer not having something that tells people when I’ve personally read a post. Seems like a tiny invasion of privacy, but an invasion nonetheless.
However, I agree that it would be nice to have a few more options for marking a post publicly. I might, for instance, agree with a post, but not like it, so I wouldn’t want to click like, but just adding another post saying, “I believe you’re right.” feels noisy to me.
However, I don’t believe this should be in the core - this is plugin territory, and someone will eventually come up with a plugin that allows administrators to allow a variety of post ratings. Like, hug, disagree, funny, informative, bro-fist, etc will appear in those forums where the administrator believes they have value.
Until then, though, like simple and straightforward.