Jack

I'm sure that something will happen and Jack will vere to the darkside. His belief in what the Winchesters are selling or Castiel not being the Father/Protector he was expecting or "hearing" his real father will shift his allegiance to evil. Forever? Probably not. I am sensing a huge sacrifice from Jack to protect those he thinks he loves (good or bad) or to keep Riftworld and Realworld from colliding.
I was not on board with a new character being elevated to recurring star status on the show. It was a big risk to hang the success of the entire season (and show really) on the performance and acceptance of Alexander Calvert's talent. Honestly I think he did a pretty good job. He seemed to have pretty good chemistry with all the other actors. I just hope that the other writers don't play his naivety too much for laughs.

Like I said in my review, I'm sure the showrunners think we're going to worry he's going darkside, but he never will if for no other reason than the showrunners are planting Sam firmly on his side. So it's very predictable that he will do something like close the rift to prove his goodness or kill his daddy, maybe even end up giving up his powers to do so, especially if Dabb has any intention of bumping him over to the spin-off, which I do think is a possibility. If he does go to the spin-off to play someone's boyfriend, then they can't have him powered up.

Very Castiel-like

First.....

Let me say, (perhaps it is my age - the decade I just entered), I do not like the floppy, side-part hair always hanging in his face. That right there puts me off the character and the actor. I know, I know, it shouldn't, but just like I can't get past Tom Cruise and Richard Gere always 'smirking', the 'hair' bugs me.

That said, if the show's intent is to introduce a character to focus much of the storyline on for the season to give the 2 leads more time off, (though I much prefer, Jody, Kevin, Benny, Bobby) I can be okay with that.

What I don't want to see is: brat-Lucifer and dumb-Cas forming an alliance to raise/nurture/train Jack, an all-powerful-Jack, (though we don't yet know what 'powers' he possesses), fixing all issues and problems and always saving Sam and Dean, Jack go all evil, Jack be all naïve and stupid.

What I don't mind seeing is: Jack exploring the dark side, testing his abilities and powers, Jack finding trouble and the brothers bailing him out, Jack joining the fight to re-cage Lucifer.......

Guess we'll see as the season plays out.

Also, Jack's father - I know it's Lucifer...but isn't that president guy technically his father too? I bet no one cares like the writers, but just a thought..