Southland had some great episodes late this season, imho, at times veering into Breaking Bad levels of intensity. Tonight's finale definitely felt like a series finale, though it's not clear yet whether TNT will cancel or renew.
I enjoyed seeing Tom Everett Scott's season 1-2 character return (Regina King's 1st partner), though it's uncertain if he's romance material or basically a nanny for her baby.
Ben McKenzie is in a CBS pilot for a show by The Mentalist's creator. So if that got picked up, he'd presumably be unavailable for Southland.
If Southland gets another season, I'd love to see the Ben and Cooper characters reunited as partners. This season basically broke both characters in emotional, tragic (and in Ben's case, corrupt) ways. I think it'd be compelling to see them help each other, rather than keep giving Cooper a new guest partner each season.
Nice recap with comments from cast at:http://insidetv.ew.com/2013/04/17/southland-season-five-finale-preview/