It would be nice if the users asking the question could preview the way the summary of their question looks on the list of questions. The current way of automatically summarizing the question by its first two lines is OK, but it may not always be what the user had in mind.
For example, some questions start with a code snippet, with the body of the question in English sitting at the bottom. The summary of such questions becomes useless, because the top of the snippet is often the set-up code. This makes the search of question lists less efficient.
With a preview of the question's summary in place, in addition to the preview of the question itself, the users would be more aware of the way the summary looks. This will improve the chance that the summary will come out good-looking.