I know cross-posting (writing the same question on more than one SE site) is discouraged and should not be done. I also see the reason for this and agree, but sometimes it is indeed not clear where a question should belong best or it would be useful on several sites, as every site usually has its special kind of experts and for some issues more than one kind would be good.
So what I would like to propose and discuss its advantages and disadvantages with you is that SE could implement a "site-sharing" feature for questions. You write the question on one site, but you have the option (starting with a reputation score of e.g. 200 or 500) to tick some checkboxes, so that it will also appear on the main/question sites of other SE sites. It should not create a clone question but instead link to the original post or create a reference that looks like it was created on the site you visit it, but is synchronized with the main post. Important is, that all shared questions are always at the same state on all sites.
You think this can be implemented by the SE team? What problems or further improvements do you see? Please express your opinion not only (but also) with votes, but rather write constructive comments and answers. Thanks!