I would like to see more heroes have better resolve and care less about virtue when it came to killing the villain. I get the idea behind it: you don't want the hero to look anything but good in the audience's eyes (another cliche I kinda don't like). But consider this:
You've built up this villain to be a truly irredeemable person. They have committed straight up genocide, slain innocent babies, and LAUGHED while doing so. The hero has been shown to be a good person. Time and time again, they've done their best to do right by other people.
At what point would I go "oh, the hero is just like this horrible villain because they killed the horrible villain"??
Kill the villain!! If you're gonna give me this irredeemable person who HAS to be taken care of, stop making your heroes hesitate to do that just because the villain gives some half-baked "we're the same" speech when it's clear they're NOT the same.
And on that note -- stop making heroes forgive the villain on the behalf of their victims.
"Like I know Lord Dickhead killed all of those villagers, robbed them of their lands, and enslaved their children, but he had a change of heart! We're friends now!"
Screw that -- it makes your hero look like an ignorant fool.
