Agreed. He’s handsome enough to pull off the whole “horror at his disfigurement” thing, and since Doom wears armor, he doesn’t have to get in shape.
Leave Iron man be. Stark is cast, and cast well.
My first thought was Hank Pym, Dr. Strange would be a good thought as well.
I don’t think Doom would be that appealing to him as he’d have to be in the iron mask the whole time, but who knows.
For DC, I could see him being the Atom or Flash possibly.
He’d do well as Green Arrow, I think.
Modeled mostly on the version from late in Kevin Smith’s run and early in Judd Winnick’s - somebody who’s been at this for a couple years, but isn’t worn down by it all; a headstrong lefty, but mostly only butts heads with equally headstrong people with opposite beliefs (politically or practically)*; likes the ladies, but doesn’t have the whole ‘cheated on his fiancee’ thing as a huge bit of his characterization.
- Rather than hectoring people like Green Lantern or Superman about not doing things his way.
No way Leo could pull off Green Arrow. Totally wrong personality. That would be as nonsensical as Ben Affleck trying to play Daredevil.
Dr Strange would be a good fit.
Dr. Strange would make a horrible Green Arrow!
Mr. Mxyzptlk
OK, why don’t we get Hawkeye then?
Yeah, there is just no possible way I could picture DiCaprio in an Iron Mask. 
