Yes, that's pretty much exactly what I was talking about. I don't know about custom reactions, but I think it's likely that there are pre-programmed reactions (similar to the heart) that staff could implement. I could be very wrong about this though.
That second part would be useful. I don't know how easy it would be, but if it's possible, that would be awesome.
mostly I agree. the mood of an RP probably wouldn't be super accurately judged by the reactions (do to joking and other OOC interactions), but it would still be more accurate than just rep. The summary at the bottom is something that seems accurate. However, I believe one of the main points about rep that people raised was that it can contribute to poor mental health. This doesn't solve that problem, but I can't think of any solution that solves that, besides maybe removing it all together. Even so, something would probably rise to fill its place, so I don't know how important of a point that is.