If future people don't like the situation, they can change it. But they aren't in the present, so they don't get a choice. The dead don't get a choice in the present either - just those present. Heck, those that aren't present don't get a choice, when the choice is made. Only those present, temporally and spatially, get a choice. As humans (and Cardassians) aren't 4d beings, we don't really care what the future thinks - and it's not like they could let us know anyways. All we can do is predict what they might want, and that's more than a little tricky, other than very basic things - just look at any past predictions of the future.