There is more to finishing besides just pure power though that plays a part. You have to place your shots well, cut off the ring, and strike at the right moment when the opponent is hurt. Ray Leonard was the best I've seen at it. Kelly Pavlik and Trinidad were also tremendous finishers. Who's the best today?
Beterbiev. I don't see anyone surviving a knock down and being able to get away from him the rest of a round let alone the rest of a fight.
Good call but I think he goes a little wreckless for the stoppage when he has his opponent hurt. I don't think he will have the same approach against Brook.
Spence is a good choice. I will put Inoue, Gvozdyk, Lomachenko, Jacobs and Beterbiev. But with the exception of the Jacobs fight, GGG is by far the best finisher in boxing.
Trying to classify someone with a 70% KO ratio in a lower weight division as feather fisted is a bit silly, don't you think?
Not when your opponents have the most losses to wins of any other belt holder or contender in boxing.