Biggest career transformations

[The Surgeon]

Surprised no one has mentioned Cotto yet. Although it's still a work in progress, he has shifted from a pressure fighter/body snatcher to a more refined boxer under Manny Steward.

I feel like Cotto has made only a slight adjustment and has merely gone back to being more patient and fighting methodically like he did on his way up, as the KO's kept piling up he got more and more aggresive but he was never just an all out pressure fighter, he fought that way against Quintana and Judah but that was smart tactics, the fans and HBO tried to pigeon hole Cotto as a Chavez type guy but in truth he was always more versatile and mobile, if less effective...

[SCtrojansbaby]

B-Hop from up until the Tito fight was an aggressive come forward KO artist

From the Tito fight until the second Taylor fight he was the super cautious counterpuncher who almost exclusively fought off his back foot

The 175 B-Hop IMO is the best one as he put it all together and instead of fighting off his back foot he smothers his opponents.

[TintaBoricua]

Obviously very recent but the first one that actually came to my mind was Floyd Mayweather Jr decideing to stop throwing combintions when he moved to 147.

I didn't follow boxing until late 2006 but have ever since been absorbed by the sport.

And yes, this is very noticeable when watching fights from Floyd back in the day. The fluidity, speed, and precision with which he could throw combinations was astounding (Mitchell, Gatti, Bruseles).

He's much more cautious when he opens up now, though.

[The Surgeon]

I guess u could say Ricky Hatton too, he was a an absalote Terror coming up, relentless and non stop but turned into a smash and grab type of guy earning him nicknames like Ricky the wrestler ect! I think it might have more to do with levels of opposition than anything else tho