Voodoo will always be for sale, kind of a corner stone of player commerce i think, but needed, without people trading voodoo casts for ships there would be a lot less interaction.
But i agree MoW shouldn't be sold. I was originally against them being able to be won in combat, as i think it would allow one player to become to over powered, and then nothing short of a large quantity of the new rare voodoo can really even dent them. Also when it's lost it's gone and i think some people will walk away from the game if they know the only way to get another one, is to attempt to do to someone else, what was done to you.