I have installed and tested a simple mod (not active, so you won't be able to try it). If you try and vote, without leaving a comment, you will receive a message saying 'You don't have permission to perform this operation.' However, if you comment first, then you can vote. The problem we had before, was not everyone has a static IP address. So, if they voted a 0 on a cover, we could see what IP address gave that vote, but the addresses didn't always tally with any members names. At least this way, the IP address left for the voting, will correspond with the IP address left on the comment. We also have the ability to allow individual groups to vote. Another option could be to only let contributors and designers vote.
If the poll goes in favour of turning voting back on, I will allow access to this mod.
CC, you (as a Master Designer) still have the option to disallow voting on your covers. There is a mod available, that only allows you to download an image after commenting. However, this is not something that most members will like. Especially if they are a subscriber. It is just a shame that more people don't appreciate the hard work you put it!