Hoi, On META I have written a piece http://meta.wikimedia.org/wiki/The_Ultimate_wikitonary In it I describe what I think the Ultimate wiktionary would be like.
In the article I assume that things like etymology, pronounciation all the good stuff that we need in a wiktionary are a given. Therefore this article is about how it works and what functionality makes it possible. The article is intended as a Request For Comments.
I also want to direct your attention to the article http://meta.wikimedia.org/wiki/Proposal_for_a_Wiktionary_proof_of_concept .. In it I propose to implement a subset of what is required for a wiktionary that understands XML. I really welcome comments.
Thanks, GerardM