Even with the current voting mechanics, non-donators still find it hard to catch up with those that pay with real money. It's even harder for new people since they need a lot to work on to get fairly strong.
Well, if this gets implemented, donators will dominate the game, leaving the non-donators and newbies to suffer a lot. Why? Because non-donators and newbies only rely on grinding, voting, and selling their spoils to get money to fund their needs, while donators could just get what they need almost anytime. And not only that. Multivoters would also suffer but legal voters are the ones who will suffer the most. Why if you ask again? Because Multivoters could just make more accounts to get the GP they need, while legal voters would stick to having at most 2 gp every day (if each vote gives 0.5gp)
Also, the economy would suffer due to the sudden changes in the Item Mall. The prices 100% exp scrolls, blessed pukerian scrolls, lucky boxes and all other IM stuff will rise drastically since they would most likely come from donating or from longer days of voting. Imagine a 100% exp scroll. Getting 12gp just for an exp scroll would already take you at least 6 days of voting. That's just unreasonable. I also doubt that the price of those would stay at 80m-100m.
Lastly, this is a private server. People go here not only for the great exp/gold/drop rates but also because they know that they could purchase Item Mall items by voting. Making vote very limited would make the server more like an official server now. I know a lot of official servers of other games that require you to pay real money just to get strong, this server would be the same if this is implemented.
Tl;dr : This would be a nice suggestion for those who donate. But for me who rarely donates and relies on the voting system, I would disagree