I think that this idea of motivation is completely unnecessary and wrong, as others say, reports should not be linked to merits or any kind of monetary motivation. No matter how such a system is designed, there will always be those who will abuse it, and I believe that the moderators would have a lot of work and a lot of reports that would not make sense.
Hmm, it's strange that the admin proposed something like that, and that nothing happened for more than 4 years, which means that it's something very low on his priority list. Given that badges were awarded in some other cases, I assume that their technical implementation is not too demanding, so perhaps part of the reason why they were not implemented lies in the fact that some do not want to be labeled as top reporters.
But I would like to remind the concept of (Seeking reporter badge images) theymos seeking images for badges like three levels and it happened in 2018 if I am not wrong but still now it doesn't been implemented. 
Hmm, it's strange that the admin proposed something like that, and that nothing happened for more than 4 years, which means that it's something very low on his priority list. Given that badges were awarded in some other cases, I assume that their technical implementation is not too demanding, so perhaps part of the reason why they were not implemented lies in the fact that some do not want to be labeled as top reporters.