It depends on the question. If the question is written so that a short answer is expected, then the answer will be a short answer.
Short hubs will not make a lot of money, hence why people do not take the time to write them. If you read in the Learning Center or some of the entries in the HubPages blog, hubs should be at least 500 words or more to be quality. Plus, from all I have been reading lately, Google is/will be looking for longer articles that are well written and have quality content instead of short, poorly written articles.
Hope that helps.