I can imagine a situation where people donating about 100 VRC are holding as strong of a vote as someone who donated 100,000.  You could get trolls coming out of no-where, getting together, and throwing 100 VRC each to swing votes in a direction that may not represent the community properly.  I think weighted votes are the only way to do it.

Something like:
100VRC-1000VRC donated = 1 vote
1001VRC-10,000VRC = 2 votes
10,001VRC-30,000VRC = 2.5 votes
30,001VRC-50,000VRC = 3 votes

Just an example.. I'm sure it could be structured fairly, albeit I'm not the best to go for advice on this but it seems like a fair method to me...