The idea to release singles itself is good imo. I've felt for a long time that every remaining MJ outtake, if it's going to be released, should be treated as a little treasure. Give us the backstory, film a mini-documentary with the collaborators and any footage there may be of Michael working on it, and upload it on YouTube. Include different versions if they are available. It could be a great way to give people an insight into Michael's recording process and artistry.
But of course, we'll probably get a crappy 'contemporization' or 'duet' every few months, with the original version tacked on for purchase if we're 'lucky'.