I agree with pretty much everything you proposed. I'm sure we're not the only Wiki with this issue, and with the goal of Tiki being pervasive in Wiki-land, perhaps these language changes within the wiki data could be made into some sort of normalization feature or mod? Every project has to take stock every once in a while and parlance changes. Weblogs in the early days are now blogs. Making a tool where you can feed it a mass search/replace list I think is valuable, for various languages, aside from leaving it to folks to hack their databases.
In principle though, I think its a great idea to clean up the english language stuff!
An advantage of an all in one app: it's easier to have consistency.
Please see:
http://i18n.tikiwiki.org/mass+spelling+correction