For the record, I already have asked theymos about changing the amount to achieve Donator and VIP status. His explanation was quite brief: changing it into something smaller than what it is could be grounds for services and people to abuse the system to scam.
Do you have the actual quote of this? Was he talking about the current Donator/VIP ranks or new additional ones? I don't think that just because somebody might take advantage of them to scam is a good enough reason. People can already buy accounts here to do that or use their already Hero/Legendary status to try pull off a scam anyway. In fact, you could probably argue that people who donate to the forum will be less likely to scam because they have money invested in their account.