Saint, I don't see Dick being Batman agian. I don't think he would WANT to
If the circumstances are right, he'd do it. If Bruce was taken out and nobody else opted to be Batman, I believe Dick would do it in a heartbeat. Letting Batman die would be like letting Bruce die. Furthermore, if someone else chose to be Batman, it would have to be the right person for Dick to accept it. If it was Jason, I think Dick would probably want to shut him down and take the cowl. If it was Tim, Dick might accept it, but even that is iffy. It was once suggested that the only thing Dick would hate more than being Batman is watching somebody else do it, and I think there might be something to that.
As for Tim being Batman I don't think "age" is an issue because really no one knows how old Batman is or Robin.
We know Robin is a teenager, and that's enough.
If age were an issue than Dick wouldn't be Batman either.
Why not? Dick is 22-25, the same age Bruce was when he started.
Amusingly, Jason is the only one who has a solid psychological reason to become Batman: as I've said before, he's got something to prove. He's been stuck in this angry, violent loop--he feels cast aside, and he's lashing out. If something happened to Bruce, it might snap Jason out of that, to the point where he would try to become Batman in order to prove to himself (and to Bruce) that he isn't just a murderer, that he can be the kind of hero Bruce wanted him to be.
Tim is the only one with the drive to be Batman--the only one who wants that sort of life. Unfortunately, he's just not prepared. He's not in that place--not only in terms of his age, but in terms of his ability.
Dick is the only one who is
prepared to be Batman, but is also the one with the least reason to be: he's got nothing to prove, and he doesn't want that life. Personally, I find Dick and Jason to be the most interesting choices--Jason because he'd be using the Batman identity to try and better himself, and Dick because he'd be trying to prevent the darker qualities of the Batman identity from affecting him.
I think both Jason and Dick would make excellent, interesting Batmen. Tim is presently the least interesting choice, in my opinion.