With the Riddler, there is an inherent silliness to the character. He likes riddles. That's his gimmick. My problem over the years is design wise how they try to make him more serious but still retain the sillier aspects like the mask and it always looks awful.
I was afraid of the darker aspect they were taking, not knowing how it was gonna be. But now that I see it, I absolutely love it. Reeves just took it to another place. I think if you're going to make Riddler a more serious threat, just go all the way and don't half measure it like in other versions. The Zodiac killer vibes is really the ideal way to go here. I cringed at the Jigsaw ideas, but Zodiac is the perfect way to do it. The U.S. surplus cold weather mask is a really inspired design for him. It's creepy, but I love how it still uses a more grounded approach where this could conceivably be what a real serial killer would look like. For the fact he looks nothing like comic book Riddler, the fact they were able to make it really creative but still feel true to him is a real commendable thing here.