Anthere-
Spreading the discussion in 150 subwikis is the lose-lose situation.
If there are 150 different active communities with a significant amount of members who do not speak English, then they should all have a place where they can discuss policy matters in their language, with a localized UI, and without interference in many other languages which they don't speak.
See my response to Daniel for how this can be achieved within a single installation, and how this principle could be applied to Wikipedia, Wikibooks, Wikisource etc. as well. Either way, we should acknowledge the need for language-level filtering, and make it a priority to implement this. That would be a good test case for a bounty system.
Regards,
Erik