> You can't make moral judgements from a viewpoint that assumes knowledge of the future.

Actually, you can. It's one of the main categories of normative ethics:

https://en.wikipedia.org/wiki/Normative_ethics#Normative_eth...

"Consequentialism (Teleology) argues that the morality of an action is contingent on the action's outcome or result", this particular category includes one of the most famous theories of ethics, utilitarianism.

Your problem with it is valid, however. As far as I've understood from my study of the subject matter, no ethical theory is perfect, not even utilitarianism.

Check out the wiki page for the other categories. Personally I like virtue ethics, keeps me on my toes and critical. I wouldn't recommend it though, I'd prefer if the rest of the world was utilitarian :-P cough