I don't think we can do much about homework questions, all stacks that deal with difficult science subjects get some of those, there are lot of homework questions on physics.se as well (see how many homework questions they get even during summer). I think outside of outlawing the homework questions there is not much to do about them. Also, personally I do not even mind homework questions that much as long as they follow our homework rules. Some people may come to economics.se for help with homework and then later stay and become regular users, and later contribute after their studies. Maybe we could make the homework standard stricter, although I guess they are already reasonable.
Regarding the vague questions from lay public, I think that is a bigger problem. I think that could be at least partially solved if we would change our rules to require question be based on some references and prior research (at least to news) instead of just encouraging it. That would get rid of all the 'shower/toilet questions' (e.g. I think the worst questions are those when someone gets an idea for some new exotic economic policy/system, likely while having late-night shower or sitting on the toilet) that are just posted here without any effort whatsoever.