These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Whatever Happened to The Man of Tomorrow?
Complete Monster: Brainiac. He brainjacks Luthor in the most horrifying way possible, murders most of Superman's remaining friends, and is completely devoid of anything resembling a conscience.
Dropped a Bridge on Him: One could make an argument for Luthor suffering this. Despite being an Arch-Enemy, he's essentially along for the ride rather than actively scheming like he might have. Of course, this doesn't make his death any less poignant.