It's undeniable that only a tiny part of current VIPs wouldn't have donated if they hadn't been promised special powers (as you call it). If you suggest to make those special powers irrelevant by giving the rest of player similar advantages, what would the motivation to donate be?
This suggestion has been made, more or less in the same way, several times already, and the answer is always the same. Unfortunately, those special powers wouldn't be have such a noticeable impact on the rest of players' gameplay if VIPs used them against other VIPs. But, as you may have noticed, practically all the VIPs refuse to shoot other VIPs (even if they aren't friends and have never talked to each other) and prefer to work together to hunt down the newbies.