Would we rather have a close/reopen vote threshold lower than 5?
Recently, Stack Overflow experimented with and decided to change the threshold for close/reopen votes from 5 to 3.
They found an increased efficiency without measured negative effects. The change has also been tested on smaller sites, which may benefit even more because it may take a long time for enough experienced users to review the question and find consensus.
The downside, discussed on other Metas, is that aggressive close-voting from particular community members may carry more weight with a reduced threshold than it would otherwise.
See also:
https://diy.meta.stackexchange.com/questions/1478/can-we-get-the-close-vote-threshold-lowered-to-3
for some discussion on other meta sites.
Other related meta posts (and please feel free to edit in others as seen fit):
Inadequate moderation by the community
New moderators, please be more reserved with your close hammer
I've posted my own answer, but of course other opinions and perspectives are strongly welcomed.