That's irrelevant. The problem I'm pointing is that Oda has made no proper effort to translate his training to his New World experience. Not only that, but this statement of yours is essentially flawed because Sanji himself explicited how the training would make him significantly stronger; therefore, Oda was making a point on his improved capabilities once they reunited (and, to be fair, if he could keep it up with some of the strongest East Blue and Paradise people nothing should stop him from keeping that routine in the New World after timeskip). I'd have bought that Sanji needed the Raid Suit after experiencing how his training wasn't enough, but Oda hasn't exploited the potential of the newkama recipes as body enhancers (I only recall the end of Punk Hazard) nor has stressed any particular result of the training apart from blue and sky walk.
At the end of the day, the problem is that Oda had all the elements to improve Sanji's strength through cooking, to merge both sides of his character, but chose to make up a (dull) family who gave him a tech suit with superpowers. That's arbitrary writing.