Short and concise may lead to not being thorough, but a longer answer might risk being tl;dr
Depends on the question.
Certainly, we should not force a short answer, because it often cannot be enough. This is a Q&A site, not a forum. We should expect that people coming here want a good answer, not a short one. If someone doesn't read an answer because of its lengthiness ("tl;dr"), they probably weren't really interested in the first place.
We should neither force a long and descriptive answer, because sometimes one cannot be given without babbling. An example of a short answer that is more reasonable than a long answer would be: What is the physical evidence for a local flood?