I think that most people will not watch Emma and Hook solve crimes because most people don’t like them being a couple and they aren’t going to have a show be about that.
My thing is not even if viewers like CS or not, my thing, was that viewers are done with duos fighting crime, Castle, Bones( that are over), Blacklist and Blindspot( that are in danger of being cancelled this year, the only thing can save them is NBC love for shows, but may be close of having a final season in the fall), the exception is Lethal weapon, but that is 2 guys and the show has the fans of the movies behind them, and that may even end on s2, but like i was saying, that is something people got bored, so having a duo fighting crime even if he is Captain hook and the daughter of Snow White and prince charming is just like the other ones, Boring, especially if we add that Emma has magic so she can catch and arrest the bad guys in the 1st 5 min of the show and then what, the remain will be to show them as married couple, again sounds a lot like Castle or Bones and we all know their ending, low ratings and until they got cancelled.
"I offended you with my opinion? Ha, you should hear the ones I keep to myself".