I'm curious about the desire to reduce ambiguity, which seemed to be emphasized as a motivation for the creation of Ithkuil and some of the other languages mentioned.
Is it desirable to completely eliminate ambiguity? I can see why it would be desirable in a scientific paper or a public political debate. But in everyday interactions, (intentional) ambiguity plays many important roles.
In my experience, politeness is bolstered by some level of ambiguity. Rather than explicitly state your needs, desires or opinions, you imply them at some level of abstraction, allowing other participants in the conversation to accept or decline more easily. Imagine Jessica who has brought two friends who don't know each other to see a play. They chit-chat a little afterwards, then Jessica goes home early leaving two virtual strangers to have a drink together. It's not hard to imagine the conversation going like this:
A: "Did you enjoy the play?"
B: "It was very interesting. I thought the stage dressing was a little unconventional."
A: "Yes, I noticed that too. Very creative. I was intrigued by the style of the narration. It really let the audience write the story for themselves."
B: "It certainly didn't constrain the imagination did it? I couldn't help noticing that many of the actors took a somewhat avant-garde interpretation of the source material."
A: "Yes, as if they didn't want it to seem like they were 'acting', so to speak?"
B: It was awful wasn't it!?
A: Thank god! Yes, worst thing I've ever seen!
Ambiguity allows subtle social cues (not so subtle in my example!) that avoid direct confrontation when it might be uncomfortable. If one person loved the play and the other hated it, they each might want to avoid offending the other.
Intentional ambiguity plays an important role in other social interactions like dating or friendship-making. Correct use of ambiguity protects feelings, demonstrates subtlety and good judgement, and avoids non-productive conflict.
In artistic expression too, ambiguity is often intentional or even necessary to the effectiveness of the work. Consider a poem like "My Papa's Waltz" [1]. Does it describe happy memories of the narrator's father, or dark memories of childhood abuse [2]? Can it describe both? Is there something in between? The ambiguity isn't a byproduct of imprecise language. The ambiguity is the meaning. To resolve it is to remove the point of the work. The poem cannot be effectively communicated in any medium that does not allow for the existence of ambiguity.
[1] http://www.poetryfoundation.org/poem/172103
[2] 'Yet, this poem has an intriguing ambiguity that elicits startlingly different interpretations. Kennedy calls it a scene of "comedy" and "persistent love", and Balakian, in part, labels it a "comic romp" (62). In contrast, Ciardi sees it as a "poem of terror"' - from http://www.mrbauld.com/exrthkwtz.html