The Batman (2021)
(Casting/Speculation/Wishlist Pt. 3/???)
First, let's talk about the name. Nashton. This was the original last name of The Riddler before it was changed to E. Nygma/Nigma in the comics. The Batman '66 version of The Riddler was named Nashton as well. So while some may complain that this is a "departure from previous iterations," Matt Reeves is actually paying attention to the source material.
Now, the character has usually been portrayed as man obsessed with being the smartest person in the room who just so happens to make Batman solve riddles to stop jewel heists...(foregoing the animated Hush adaption, smh 🙄) there have been rumors as far back as the Nolan days of them doing a serious take (read: not Jim Carrey) of The Riddler.
I remember rumors of Johnny Depp being cast as a version of Riddler that was more akin to Jigsaw from the Saw franchise or Kevin Spacey in Se7en than a riddle-obsessed jewel thief. While they may still take a serious approach like that, I doubt/hope it won't be of the Jigsaw variety....I would hope they would save that kind of twisted for someone like Hush/Joker/Professor Pyg...etc...
Now if it were up to me, I'd do something fresh: Nashton is a military E.O.D. specialist who studies and inadvertently becomes obsessed with riddles due to TBI sustained in battle, comes home a wounded veteran, he fails as a S.W.A.T. Cybercrime-specialist (due to hacking people's computers in order to prevent crimes from happening or something 🤷♂️) and then becomes obsessed with Batman's identity (pissed that Batman can violate the Patriot Act and spy but he can't) and becomes a domestic terrorist/serial-killer who's obsessed with outsmarting Batman to tear him down...well that might work...
When it comes to the look, I think it's a no brainier here to go with either the Earth-One look or the War of Jokes and Riddles look. Say what you will about that story, but Paul looks very close to this version of Riddler. I doubt we're going to have a Shredded™ version of Riddler anyway, or even one who walks around with his shirt unbuttoned for that matter.
But hey, the trench coat is cool...just lose the question mark tattoos/scars. Don't need a repeat of Edgy Joker™ from Suicide Squad...