I don't know if this has been suggested before, but could the tombstone reaction be changed to give reaction points?
If the axe reaction was changed to give reaction points, and it's absolutely only used to express disagreement with something (yes I get the intention behind it but nobody uses it for that), I don't see why the tombstone reaction shouldn't be changed to give reaction points as well. For the most part it seems like basically an alternate laugh reaction and so I think it should reward reaction points as such. If you really want to react to someone with a grey rock and not reward them with points for it, you can use the boulder reaction.