I thought it was a nice wrap-up of the series. Quite satisfactory all around.
One thing possible plot-hole did stick in my mind, though. They managed to undo the effects Jafar's use of breaking the laws of magic (and we saw that with Anastasia returning back as dead), but why did Cyrus stay alive - he was alive from Amara's breaking the laws of magic (or did Jafar kill him after the spell was finished?).
I've heard that Will Scarlet/The Knave will be appearing in the main Once Upon a Time next season.