I understand the danger of tactical downvoting. It's clearly gaming the system. But what about Community Wiki posts (on Meta, at least)? Nobody is there to gain rep; there is no reason anyone would possibly want to tactically downvote anything.
After witnessing active Meta activity in Area 51 sites, where the environment of the entire newly-formed website can change and shift drastically within the time span of even a few days, very important Community Wiki meta questions can see answers shift from extremely relevant and helpful to horribly irrelevant and even destructive to the progress of the developing community.
I'd perhaps like the ability to be able to change positions that I support over time, as the landscape of the issue changes drastically around me. And I really don't see any downside, honestly. If anyone has any, please point them out.