I have a few thoughts on this...
First, if we're gonna do this then let's make it worthwhile: 1 vote == closed, regardless of how many other votes or flags are in play. My biggest beef with close voting is the execution-squad attitude it seems to inspire among folks: "oh, I don't want to take responsibility for closing a question, I just want to be one of the mob throwing stones". If we're gonna give more weight to votes from folks who according to their past participation we should be able to trust with them, I want them to be taking that extra responsibility seriously.
Second, this power should be based on the tags in the first revision of the question. I know, that cuts out a lot of potentially-useful effects when it comes to niche tags - but it also cuts out a ton of potential for abuse, without also making it a major headache to figure out what a given vote is actually worth. For the tags where this actually matters, it matters because they happen to also be the most obvious tags for a whole bunch of questions - if you want an answer, that is.
Third, this has to apply to re-open votes as well. Philosophically, it's just the right thing to do - but it also makes sense from a practical perspective, since you can't undo a binding vote if you make a mistake or the asker fixes their post.
Fourth, normal limits apply: you get a finite number of votes, and you can't vote twice, even if the post gets re-opened, even if you re-open the post. No gold member close-wars!
Lastly, there are not that many folks with gold badges floating around right now. Here's the breakdown by site:
1845 Stack Overflow
17 TeX - LaTeX
10 Server Fault
8 Super User
8 Database Administrators
5 English Language and Usage
5 Code Review
4 Role-playing Games
3 Unix and Linux
3 Drupal Answers
3 Jewish Life and Learning
2 Personal Finance and Money
2 Science Fiction
1 Home Improvement
1 Game Developers
1 IT Security
1 Graphic Design
1 Code Golf
1 User Experience
1 English Language Learners
Yes, that means the gold tag badge users on Stack Overflow could, in theory, close 92 thousand questions every day just by using all their votes. That's 10 times the number of questions SO actually gets every day. Think about that a little bit.
So... What if we had silently implemented this on Stack Overflow a year ago, and no one had altered their behavior...
- 22,102 questions currently open with pending close votes would instead be closed.
- 145,843 questions currently closed would have been closed faster and with less effort needed from other voters. 90,722 of these would have been closed with a single vote.
- 34,837 questions currently open would have been closed instead of the vote aging away. Note that 11,677 of these went through review and were marked "Leave Open".
- 2,677 questions would have been closed faster, but then reopened anyway.
- 1,328 questions would have been reopened faster
- 1,837 questions would have been reopened instead of the vote aging away. Note that 1,829 of these went through review and were marked "Leave Closed".
- 1,071 questions would have been re-opened faster, but then closed again.
Note that during the past year on Stack Overflow, 362,220 questions were closed and 8,108 questions were reopened.