If the Germans had reached Antwerp, they would have driven a wedge between the British and the Americans. But this would not have been much of a problem, as the British would simply have hunkered down while the Americans blast their way through to get them out, in the process destroying the last major armored forces of Nazi Germany, and much else besides.
End result: Berlin falls a month earlier than IOTL.
A MUCH better strategy for the Germans would have been to use their carefully built-up armored reserves for small-scale counter attacks designed to improve their positions in preparation for the inevitable Allied spring offensive, and to inflict heavy losses on the Allies. And rather than throw away 1,000 planes (and, more importantly, pilots) that they couldn't afford to lose, it would have been much better to adopt Galland's plan and use them in a surprise "Big Blow" against Allied bombers, which might have inflicted such heavy losses that the bombing would be temporarily lessened.
Of course, this wouldn't make a damn bit of difference in the end, and would only delay the fall of Berlin by a month or two.