There was a manip of him with short blond hair in the suit with the cowl off. It sold me. Whether with dark hair or not, he'll be fine in the part. Grant Gustin also looks nothing like classic Barry and he too was thought of as too young. Yet here we are months later and the outcry that accompanied the release of the CW Flash costume picture has disappeared and now people are complaining "Why can't Grant be the movie Flash too?"
Miller is a very good actor and he's young, really young. He can easily add a little extra weight and fill out the suit that Wilkinson is going to (or already has) come up with. The resemblance thing is low on my list at this point.
I still don't get this resemblance issue when it comes to comic book characters. He's a white guy. They're both white guys. What's to resemble?
Maybe it's just my perception of what I always thought Barry Allen would look like if brought to life on the big screen.
And again, I'm not really doubting Ezra's ability to pull it off, but you have to admit....looking somewhat similar to what's been established of the role (both from within the comics and other forms of medium) does help imho.
I think an good example of this would be when Tom Hiddleston had auditioned for the role of Thor. The actor has charisma and (imho) sufficient acting skills, but everyone who was involved with the production was in agreement that he didn't "look right" for the role of Thor, hence why he was selected to play Loki instead.
Even when Cavill was first announced for the role, if I remember correctly, a good amount of folks over here weren't really familiar with his previous work, thus there was a issue of whether he had the acting ability necessary to play the role. However, a lot of people did agree that upon seeing him that they thought that he could pull off the look in appearance alone.
Plus, it's not exactly the easiest thing in the world to find a picture of Ezra (that hasn't been manipped) where he doesn't have either lipstick on, or long shaggy hair with a goatee/beard. Plus, in some photos, he does resemble a lot of Asian-American guys that I've known and seen.
But nevertheless, from what little we've heard so far...it seems like Snyder specifically chose him since Ezra said that Snyder contacted him personally to inform him of his selection, a role that he didn't even audition for.
So Snyder must have something up his sleeve and he does have a good track record for transforming actors to look like their iconic roles. So I'm really in a wait and see mode.