Here are the list of candidates:
1. Terrence Crawford - beat Spence, another pound for pound boxer, and then captured and unified all the belts at 147 lbs?
2. Devin Haney - undisputed at 130 lbs beat Loma, move up in weight and then dominated Prograis to win the WBC belt?
3. Naoya Inoue - move up in weight, challenge the best champion at 122 lbs in Stephen Fulton, then unified the belt against Marlon Tapales, second man to do so, unifying belts in 4 belt era in 2 different weight classes, second only to Crawford.
If I have to vote, then I will go with Crawford as fighter of the year, the way he dominated a great fighter in Spence, with 0 losses in his record and everyone thinks that this is a close fight. But then Crawford took everything from Spence that night and then he captures his 2nd unification belt in 2 weight class and put his name on the record and cemented his legacy? For me he is the BOTY.
For Haney, his win against Loma is questionable and although he won another belt in 140 lbs, Prograis is not that high level boxer to be honest. His previous win against Danielito Zorrilla shows sign that Prograis is slowin down already and the Haney's know this.
For Inoue, he beat Fulton, but it is expected, same with his conquest of Tapales, odds is like 1.07 so again he what we call outstanding favorite to win that fight.
So Crawford, Inoue and Haney in that order for me.