Rebranding is one of the toughest things a company ever does. There is always blowback. See Pepsi and GAP for example. GAP even had to go back to their original. The reason being, people associate all their memories and feelings of the brand with the logo. A change is jarring.
If the Miami Dolphins logo was just a fin originally, and someone proposed an anthropomorphic disney cartoon dolphin wearing a helmet as a change, I guarantee the reaction would be that the logo is terrible. Feelings aside, just looking at it from a design perspective, the current dolphins logo is antiquated, somewhat ugly, and not befitting a modern football franchise. Its a holdover from the 60s era of sports logos animals wearing sportsgear.
I realize this redesign isnt the best, or even everyone's cup of tea, but at least it functions as a logo. I want to see what people think about going toward a "fin" logo more than the logo itself as designed.