It seems that tag excerpts are not displayed verbatim/in full on the Tags pages. That's fine but it makes it very hard to fine tune tag excerpts to display optimally, especially for editors who must go through the suggest > vote > approve process for each tweak.
- New tags page mangles tag wiki excerpts
- Why is the Etymology tag excerpt missing some words on the Tags page?)
I assume there is a set of rules the excerpt display code goes through to trim the excerpts, and also that this set of rules will be tweaked from time to time as the developers find more heuristics.
So why not reuse this excerpt trimming function to implement a live preview of the tag wiki excerpt as a partner to the live tag wiki preview? This way we can be sure that our tag wiki edits, even if they are mere suggestions, won't be mangled in ways we cannot deterministically predict once they make it through to the Tags page.