This is almost a verbatim copy of a question with the same title on Home Improvement Meta. It goes to the point and I don't see anything to be improved or expanded.
Other sites can have whatever threshold is most appropriate for them
We are "other sites".
There's only a handful or so regular reviewers in general (of the non-mod variety anyways), and closure tends to be a pain: it takes days to have a question closed. Lowering the threshold to 3 would ensure faster community response time.
In short, let's set the close and reopen voting thresholds at 3 instead of 5. As this is a feature request, you can use the upvote and downvote to show that you are for or against the proposal.
As read in CM Catija's answer to Is it possible to reduce the number of close votes needed for certain types of close reasons? in Japanese.SE, this change is not straight-foward:
The number has to be the same for every close reason but we can change the number required to close a question to 3 or 1. We've run a couple of tests on other sites and are willing to test it on others. If you'd like to run a test here, have a discussion about it and then have one of your moderators ping me once you've made a decision.
I have a handful wanting to test in January already and I'm not sure how many I can do at once but what I generally do is a one-month test and then we compare some stats before and after to see what impact the change had. We're being cautious about making the change permanent from the outset because there's some concerns we want to avoid.
Here's some examples of sites that have tested this out or are asking whether they should on their metas: