I don't think the options are as wide open as you seem to suggest. My recommendations would be to build decks based on the current MWL, with an eye to what impact it will have if the most likely suspects get added. I think we all have a fairly good idea what those suspects are, and can plan accordingly.
This creates two lines of preparation. You are either wanting to use said suspects yourself, and/or need to prep tech for facing them. In the first case, have an alternate build ready for not including them. In the second case, tech for playing against them and consider what options you would include if they aren't likely to appear.
Oddly enough, these same considerations are not terribly far from trying to predict the meta. Have a Plan B ready for when the MWL gets announced, and you should be fine.