Instead of reposting pros/cons here again to make it into yet another forgotten post, those who care and need it should create a table on wiki with clear structured comparison.
It seems to me that the putative review manager (Robert) should canvass for solutions (there appear to be at least three now), do a quick check of them to see what tradeoffs each has, and make that table summarising their different approaches. He then could take a quick straw poll of here to see which set of tradeoffs the community dislikes least, and encourage that author to get their solution ready for review by an agreed date. Some have argued that all this is too confusing. It is in my opinion no different to any other Boost library. Somebody becomes willing to invest the time and effort to get a solution to a problem past review. Whichever successfully passes muster here is what we adopt. It's exactly the same as any other Boost library, and calling on the Steering Committee to declare a design by decree is the wrong way of doing this. Niall