I've been seeing an awful lot of very substantial wiki suggestions, mostly from one editor. Some seem reasonable enough, although hard to verify thoroughly; some are arguably wrong. Either way, approval is basically just a matter of approver whim or impressions, rather than of strict correctness.
(I'm also seeing a lot of excerpt suggestions from the same user. Most of those are less "usage guidance" and more "quick summary of idea", which is of dubious merit.)
In order to make wiki approval more reliable, I can see two approaches. One is to build up wikis in bits and pieces, making sure each suggestion is correct and minimally complete before moving on to expand on the subjects more. So a three paragraph wiki might start out as a sentence or two covering the three points, then expand into a sentence or two for each point, then expand into the full paragraph form. This would allow reviewers to get a better sense of the structure and verify at a deeper level.
The other is to draft tag wikis here on Meta before posting them. This allows comments before the initial wiki revision, which could produce a better basic structure and allow more communication. If this route is chosen for a tag wiki, this question would serve as a good place for such drafts, posted as answers.