It definitely depends how the battle is won.
Béhuchet (the french commender) refused to consider his Genoese counterpart (Barbavera) advice to sail at sea as to avoid being stuck in the estuary : while Béhuchet's plan was to prevent Edward III to advence deeper in the close hinterland, but couldn't manoeuvre or undergo a really efficient board and fight tactic as it was common.
It also seems that Flemish ships joined the battle only later due to a favourable wind. With enough advanced action, maybe Franco-Genoese could have pulled, if not a victory, at least a stalemate, preventing a Plantagenêt-controlled Channel (basically what happened during the Caroline phase but earlier)
If the English fleet pushed back, the chevauchée (more or less glorified raid) that followed historically is obviously butterflied with small changes in the initial part of the war, but as Plantagenêt's ressources are still largely intact, it's only a matter of time before another campaign is planned and realized. Besides a major non-military event, It may not affect History in a really meaningful way.
Is the fleet, at the contrary, undergoing noticable losses? There we'd have Edward III having to drain its ressources more, delaying significantly further actions and loosing some credibility on the political side of the conflict.
In case of severe losses Flanders would be definitely threatened by Valois. I don't think that France could likely realize such a victory tough, but it would be a significant blow to Plantagenêts' cause not only in France (not even talking of Norman nobility but as well Flemish) but maybe in England too. I don't think it's nearly enough to end the conflict, but Valois would be in an even more favourable position.
Of course, if Edward III dies during the battle, it more or less add even more to both kind of english defeats at Sluys, and at best a 10 years (take or add some more) gap before a new English campaign which would definitely favour Valois, and changing history in an obvious way.