I've been a member of SO community for several months only and during that time the close questions queue size has increased significantly - by about 30k. In my opinion it is important to reduce the closed question queue size, to make sure that the community's effort is placed in valid and useful questions.
All presently used queue-shrinking functions don't seem to be working well enough.
I must admit I have not been reviewing close votes too much for some time now. The sheer amount of those votes discourages me from doing that and whenever I do do it, I feel a sense of pointlessness. What can I do against 80k questions?
I propose weighing close votes based on the reputation of the user issuing the vote. For example, like that:
Users with 3k-10k reputation weigh 1
Users with 10k-20k reputation weigh 2
Users with 20k+ reputation weigh 3
Not only will it effectively lower the amount of votes required to close a question, but could make users with more reputation review them more often: "since my votes matter more, I'll do some reviewing".
//EDIT
Another possible solution is to weigh the close votes based on the voted to close/actually got closed ratio. For example:
at least 1k cast close votes and 80% were the actual outcome: weigh 2
at least 3k cast close votes and 95% were the actual outcome: weigh 3
other: weigh 1