But again, observation doesn't work with the actual attack but the intent behind it. Before Katakuri saw the future only the priest was about to attack, but then Sanji had to deal with two intents and, therefore, adjust his answer to them. Two intents but one attack from a first commander is still more difficult to handle than one intent and one attack from a fodder, simple as that. And i'm not saying that he displayed future sight because I don't think he did, but it is undeniable that dodging Katakuri's anticipated shot was remarkable, otherwise Oda wouldn't have made Katakuri be surprised by the feat.