@Olker, as i mentioned above, people might not spend so much effort to buy ratings while the cool down exists unless the reward is very valuable. If the reward at the end of the month is around a value of 40k, it makes no sense in buying so many ratings for even half its price, because he might have to spend around 20k minimum(my assumption) and find enough players to sell him all these ratings(which itself is a frustrating task). I do believe this will counter the money for rating issue.
@Isildurr2x, I was thinking maybe if people with very low rating in pvp may get a lower priority in matching pvps,
people with very low rating in trade may get longer cool down to send text in the trade chat, whereas very low rating in All or help chat must get a cool down to send messages in the respective chat just like we do in trade chat. This idea might also backfire if people do get to abuse the rating system, so currently my best opinion is to just show a reputation indication in every players trainer ID while having no consequences in his gameplay. People trying to get the lowest rating is also conserning in this case. But even with no rewards, if someone tries to get 0 stars, if they behave poorly intentionally in PVP,Trades or in chat they risk the possibility of getting reported or later banned or get ignored in the case of blabbering in the all chat. For a better understanding, this rating will be like the imdb movie ratings, it only tells the people how good the movie is in popular opinion, here this rating just shows how good of a reputation he/she has in the game in terms of PVP, Trade or in the Chat systems. It dont affect you in any way even if you get rated poorly by the entire server.
@Acetzy, Maybe try behaving nice to other players like you always do and help each other. 😄
@Lyn1311, I have tried to consider a counter for all the ways it could go wrong but we cant say anything unless it is tested. 🙂