I agree with you about mission statements in general. Corporate fluff for the most part. Read once when hired and then only seen in annual reports. Perhaps try to think of it more as a philosophy, an elevator pitch or a marketing blurb, all of which, including a mission statement, are things that you've been trying to come up with year after year without consensus or progress.
It was actually your suggestions in this post,
https://groups.google.com/forum/?fromgroups=#!msg/habari-dev/rzyMnWyItYA/RA3Ql9cjSEMJ along with input from others, that motivated me to give it a go.
Just as programming code is never perfect, the same holds true for marketing code. What I see this as, more than anything, is a way for people to find the project, quickly assess whether it is something they are looking for (in under a minute) and perhaps even motivate them to contribute or give it a try. An SEO bumper sticker if you will.
People don't search for spiritual goals in Google. They are looking for an "ASL open source blog project", "lean CMS dev kit for multisite blogging" "multilingual multiple author blog platform". Or, at least if they were, they would not currently find Habari.
The real question is, if you saw this as the blurb for some other competing product that you had never heard of, would you be intrigued enough to investigate further.