I think not everybody is interested (or have just-in-case time) to read the whole answer (which contain Ayas, Hadiths, mental trail, etc...), there are many people who may need to get a quick answer for their questions (maybe because they're in a hurry at the same moment).
Well, since the community will choose the best answer at last, I see no problem in having a short version of the answer at it's beginning. In truth I find it very useful and will help too many people.
For example, see this answer, If there were a short answer in the beginning that outlines the answer and then the answer which you see now, then it would be very nice in my opinion.
What I mean having answers in this form:
The short answer which is the outline, it's for common people and people in a hurry.
The real well-cited and complete answer which the short answer depends on and outlines.
This situation is common on StackOverflow when the answer contains very long explanation.
What do you think? do you agree or disagree?
P.S: Note that even if you agree, this shouldn't be obligatory, it's only a recommendation.