1.) Minimize trauma and emotional scarring to the batkids. Scarring to Bruce himself is not as much of a concern, as A.) I don't think many people are overly concerned about his mental wellbeing and B.) Batman without scars is like Hello Kitty in a mask and tights, or some kinky male stripper or.. I don't know, Jack is better at the metaphoric punchlines than I am.
2.) Age Bruce up in a believable way, at least in-so-far as comic physics and plotlines are believable. No simple deus ex machina.
3.) Fix Bruce. Want to see some stabilization. Again, not wanting to make him into Captain America, but he needs to not be one bad day away from Arkham.
4.) Don't be a shitty writer. Enough said.
{Scenario #1} Dick finds Bruce in a cave somewhere in a cocoon of some sort. There's probably a lot of other peoples in cocoons too. Maybe Bruce went there to save people. Either way, he gets trapped, and the spidery-demon thing slowly sucks the life out of him or sommat, aging him up. I am hesitant here, because it's really freaking hard to trick the Batman. But, there have been more than a few times where Robins have either solved the riddle or flat-out saved Batman's life. So I feel like maybe it's still within the realm of Batman. And maybe the weakness will.. ah. Endear him or something. Maybe put off the 'getting his ass kicked' part for a while.
{Scenario #2} Kinda similar to Scenario #1, but Bruce has more control over it, I guess. This one isn't terribly well developed, but basically he seeks out... some sort of... healer witch mystic... person. They agree to fix his brain/restore his soul/however you want to say it, but at the cost of some of his vitality. Or whatever. (I just got the '5 minutes till bedtime' warning.) I find this one sorta boring. Needs more to flesh it out.
{Scenario #3} So, this is probably the meanest one, and accordingly it's my favorite. Having him get whisked away to another universe for 40 years or sommat and then get shoved back into UTR-verse. This would give me a fun opportunity to explore some different ideas... It's a matter of making sure he can keep his emo from the kids. Well. Blend it in to the other stuff. And I do have to make sure it makes him more sane... Which I think it would, with what I'm thinking of doing during those 40 years.. He'll be back to brooding but not ANGRY AND ALMOST EVIL. The abyss, thing. He'll be pulled far far from the abyss. Which is good.
I need to write up some prompts and talk to Jack about comeback plans.