I don't think having an answer take a while in Q&A is such a bad thing. Q&A is meant for common, general questions which will help many people down the line. As such, the answers should be fairly general and definitely well thought-out. These two things require more time than firing off a quickly hacked solution or workaround. Questions regarding how to do something very specific should be put in SOPW, since the whole site is set up to prioritize those questions. I still don't think the warning in Q&A that many valid questions are inappropriate for that section is big enough; perhaps mentioning that answers are likely to take longer and not relate as specifically to the problem will discourage people (especially AMs) from posting off-topic questions.