Canelo is not flat footed. At least not always. He takes steps in ways you don't notice because he does it at the last second when he dodging or using counters. Especially recently he has greatly improved his foot work. He's not some sort of fleet Footed Camacho type, but for his style it works quite well and he's never just standing completely still. Not really, Duran wasn't a dancer or mover but he did make plenty of subtle adjustments and steps with his feet even when he was fighting on the inside. He'd reposition himself to get better leverage or to set up sneaky shots from outside his opponents field of vision. He wasn't just a stationary come forward guy at all..
I’m not sure Joe Louis was naturally flat footed but simply chose to stalk his opponents that way. When you look at his footwork against Max Baer both moving in and out obviously respecting Baer’s power a lot of that fight he moved beautifully on his toes jabbing and moving.
a lot of people misinterpret Joe louis/Sam langford flat footed style as a lack of ability but really its pressure by moving forward and drawing leads, Watch Langford vs bill lang really carefully . Notice Langford walks forward (with rear hand ready to parry jabs , ) and takes a really long time and gets really close to Lang before lang panicks and goes for the tie up, other times Langford can Launch a lead right in range that will hit his opponent ,because Lang was very resistant to throw a jab at Langford. But thats the game , when you watch other fighters like benny leonard or jim driscoll. they use the milling motion of the jab and hop back to draw your jab out to counter you. Langford (and joe louis) use the idea of walking into range on you , to draw the jab . Whats the punch you use to prevent someone from walking all the way up to you(the jab)rather than hop back and forward or circle,Langford will walk towards you ,wanting you to jab to stop him from getting too close(he then counters that ) or if you dont do it as often like BIll lang , then Langford would just hit you with a lead hook.lead right or anything he wants . Its really really good pressure fighting.
You would think of this thread being about a Policeman walking the beat( A Flat Foot) that liked to engage in fights, Lol. But seriously, many heavyweights and fighter from different weight classes from the 1930's, 1940's, 1960's, 1960's and 1970's.