Responses asking "why would you want to do that" unfortunately are too common when the seeker is asking ("if possible" and) _HOW_
Although my use case wouldn't involve "wish" item type, I do believe the app's implementation would benefit from introduction of one or more additional item "types".
As an example, a posttype="article" would, I believe, encourage greater contributions from "experts". The poster's representation (and viewer's expectation) regarding an "article" type post would be that it (the content page, or "node") presents factual, if not entirely comprehensive and probably not authoritative, content. Perhaps no "answer" type reply option should be provided to viewers of such a node ~~ solely a "comment" type option.
Similarly (or perhaps alternatively, in the context of putting ONE additional "custom" type to use) an itemtype="discuss" might suppress the "answer" option (neither a definitive, nor "best" answer is expected).
Here's a good example (I think so):
In this q2a metasite, we're relegated to blindly searching across xx pages of possibly related... or posting a fresh (possibly, er, probably redundant) item. Whoa! a question like "How can I optimize q2a?" is MUCH too broad ~~ that topic cannot be comprehensively discussed in a single "item" thread. However, one, or a few "DISCUSS: optimization -- database" and "DISCUSS: optimization -- server" -type threads could (and would) serve as exploration starting points.