Since Colin's a series regular, I honestly don't see him dying any time soon. Both Barbara Hershey and Michael Raymond-James aren't regulars, so I wasn't surprised to see Cora killed off. There's a rumor circulating that Neal might be next, so that wouldn't surprise me, either. I personally think Killian will eventually find peace...not sure if it'll be because of a new love or forgiveness.
He really has. o-O I wish the writers could keep their characters more consistent. lol