I'm not sure how your suggestion would differ from the way direct questions work now. Are you saying you'd like to be able to ask the same direct question of several different people? Or have direct questions that other people can answer as well (which would make them public questions)?
If you want to encourage someone to answer a public question you asked, I would simply direct question them something like, "I would really like to see your answer on QUESTION URL" Then, you could add a tip to the direct question if desired. I've been asked several direct questions--both privately and publically--by people who wanted answers about something from me. Some are general questions but some have been about ADHD as well (something I am somewhat of an expert on ).
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.