I think he would. He's auditioned for the role before, so we know he at least has general interest in the part. It's proven to be a meaty role when in the right hands, so he has plenty to work with as an actor. But there's another incentive for him. Gyllenhaal is one of the best actors working today, but the simple fact of the matter is his films tend to under-perform at the box office. To use a recent example, he absolutely crushed it in Stronger, but the film did remarkably poor financially and he's been a complete non-factor this awards season. His talent is undeniable, but he's struggling to break into "household name" status.
A role like Batman changes that with one press release.