I just don't like his look for Bruce or Batman. Especially not what I think they are going to go for, which is a more comic book take (instead of a Tim Burton type take). He just doesn't fit that.
But The Joker on the other hand... holy ****. I can absolutely see him as the live action version of the DCAU/Arkham Mark Hamill style Joker. They need to cast him for that role.
I understand what you say when talking about a
"Tim Burton take" and it's true.
Even if I think Driver could work for a lighter Batman
(compared to Battinson), his natural strenght would probably be more suited for something less
classic than what Gunn seems to be aiming for
(and I don't mean "classic" as "less intersting").
I originally wanted to end my post by saying that I could also see him as the Joker, but I forgot...

Again, his ability to be funny while looking like he could snap at any moment could work great. He also seems to know how to use his voice...
I love Groff a lot and I was the first one to fancast him back when The Batman was casting, but idk if he's necessarily the right pick for a Batman like this. He's in the right age range but his face is still boyish looking so casting a Bat-Family around him, especially Nightwing and Jason Todd would be really hard. Also very secondary since even though Gunn said he wouldn't actively be trying to /not/ be Matt Reeves, I do think there's an argument to be masw he's a bit too close to Pattinson.
.
Yep. I know many won't agree but I would have the same
problem with him that I had with Hathaway in Catwoman. They are good actors, nothing to say at all about their performance, and they can even look good in costume... but on some os these very archetypal roles (
femme fatale, etc), I think you also need, or at least I need, a
"little something extra" in there. A certain charisma or
vibe, whatever you call it, for me to really buy it.