I like macho action protagonists if I can easily picture them crying nude on the bathroom floor

Good standards!

I hope he has multiple horrible breakdowns; it seems like he has good potential for it.

Ooh, that sounds fun!

It also feels like there's more scope to mess up cases in Person of Interest; in a standard detective show, of course the murders are always going to be solved, because otherwise there's no narrative payoff. I'll be interested to see whether any cases do get fumbled.

Yep. Also, I'm wondering in what sense they're investigating murders that haven't happened yet. I'd love it if a pre-crime scenario was about the least damaging intervention that would prevent a murder. (One of the interesting flaws in Minority Report was about the fixation on jailing people for crimes that hadn't happened yet, and I'd like to see more "try to interrupt them before they get into a murder headspace" stories.)