Human rights make all of that impossible.

Not impossible, but this is why the application of human rights is the issue.

Actually, I favor much lower standards of evidence for the most serious crimes/most serious penalties.

This is unspeakably retarded with the massive history of falsely accused being killed only to be vindicated post-death, which is exactly why it IS so hard to execute people today.

What do you do when someone is executed for crimes they don't commit? "Oh, fuck, I'm sorry"? That's not good enough, that's not acceptable.

"We'll do better next time"?

That's raising the bar for evidence.