Wikimedia-wide WikiProjects (narrow focus)
Fragment of a discussion from Talk:Task force/Wikipedia Quality
Global project may be useful just we should not be blind to its limits.
Lack of similar guidelines and MoS. For example English Anime/Manga project is stricter in term of notability than its French equivalent while there is nothing as Fair Use in the whole French Wikipedia. So cross-wiki collaboration should focus on content/sourcing and avoid the rest.
Lack of exactly equivalent scope. English Anime/Manga focus exclusively on Japanese Anime & Manga (What an pleonasm) while its French equivalent expand to Korean Manwha and Chinese Manhua (more pleonasms) plus western produced manga-like comics.
Global project discussion page should be transluced to each local project talk page to maximize reach & participation.