As far as season finales go, "Father Frank, Full of Grace" isn't much of one. It lacks the pathos of "But At Last Came a Knock," the wild playfulness of the earlier episodes, and even the frenetic pacing found in other Showtime season finales. But it is a solid episode of television, which, while not exemplary by any means, is a fine way to end the season. The episode cuts out most of the subplots, ignoring Kash, Mickey, and Mandy, focusing instead of the problems setup last week, Karen videotaped sex with a drugged Frank and Steve getting run out of town by Tony.
The most important cliffhanger-y event is Fiona not leaving with Steve. While this isn't unexpected, it's clear Steve is still an important character who will be a big presence in the second season even if he isn't present. Steve makes a good case why she should leave--her age when all the kids graduate and how others could take care of the family. But ultimately, Fiona refuses to leave the family, much like she refused to let Monica take Liam, and takes the job with a steady income (though Jasmine has to be up to something, right?). Steve, realizing that staying out of prison is his first priority, takes off. With both admitting they love each other, this is a problem of different priorities, and unless those change there are many boundaries between them. Not only that, there is still Steve's secret life that needs dealing with (assuming Fiona's reassurance to Debbie pertained only to the car thefts).
Meanwhile, Tony basically stakes his claim on Fiona, plunking down money to buy season tickets for the detective to let go of Lip and Ian. Of course, he's only doing this to stay on the good side of Fiona, and hopes that Steve leaving will be the ticket back to Fiona. To me, Tony is really creepy/desperate, continuing to pursue Fiona even when she's unavailable and abusing his power to get her.
Frank remains a real enigma as far as his morality goes. He seemed really out if it due to drugs at the end of last week's episode, so sex with Karen isn't really his fault, and next day he tells Karen it can't continue. Compared to the British Frank, he's practically a saint. But then Frank talks, and talks, and talks, trying to justify what happened. Lip smacking him with the car didn't seem so bad after that, and getting peed on was fair. This is Shameless, after all, and pretty much everything is forgiven in the end, as we see Lip and Karen together again.
The real victim of all this is Eddie, who started the season living with his wife and daughter, got replaced by Frank, and kills himself over the humiliation of his daughter's video.