Perhaps an "inter-stack" feature could be added to deal with question like this that are applicable on another stack as well. Such a feature would allow a single question and answers to appear on multiple sites. Reputation and badges could be awarded to the stack from-which the viewer came - or in the case of search-engine traffic make the user choose which stack to join before upvoting.
In the case of a question that is potentially on-topic for multiple sites, the best thing to do is play to the strengths of each site by asking a tailored question that focuses on the aspect that is most topical for each site. You will get much higher quality answers to a specific question that is more focused on the aspect of the question related to the site scope.
Each community has different approaches to questions and the extra time invested in learning these and adapting questions to them is well worth the effort.
Catering a feature to people who want to ask broad questions and are too lazy to spend the extra time to narrow down their scope or cater them do a different community is not something that I think would generally enhance the quality of content on the SE network.