I know everyone wants these guys to be Batman, but I just never saw it for either of them. As a huge JLU fan, I feel like the current DCU is taking lots of inspiration from that show, and just general vibe.
Jensen - The Question. I know its almost a crime to hide this man's face but his commanding voice and presence on screen I feel would demand enough attention, you wouldn't have to worry about it. I envision him poking around the world of DC, investigating/uncovering big plot points. Similar to Damien Darkblood in Invincible
Alan - I mean, the guy is huge. Physically it makes all the sense in the world for him to be nuclear energy incarnate. I would love to see James continue the trend as well of "big name actor in smaller hero's role, while not-as-famous-actor takes the lead." Think David Corensweat as Supes, while Nathan Fillion was Guy Gartner.
Let me know what you think!