Recently I fixed a lot of wikitable syntax issues with this script: https://github.com/liruqi/wikipedia
This is a by-product of https://github.com/chinapedia project, which tried to export Wikipedia data to GitHub with Pandoc. Pandoc is very sensitive to wikitext syntax issues, while wikipedia.org build-in interpreter is not. Most of syntax issues are related to wikitable attributes and styles.
This script would read error log and try to rebuild the first line of wikitable.