Would Wellington have attacked, if Napoleon, knowing he could not implement a timely attack on Wellington's defensive position, focused instead on the Prussians, then returned to Wellington when the weather was more favorable?
While modern military theory favors blitzkrieg in the attack, at the time of Napoleon, Wellington, and Blucher it was the defense that was stronger.
However Napoleon normally outmaneuvered his opponents so that it seemed like Napoleon on offense was always stronger than anyone else on defense.
At Waterloo however Wellington proved that the defense is stronger than the offense between opponents of about equal strength.
Blucher showing up at Waterloo to outflank Napoleon and reinforce Wellington tipped the battle in Wellington's favor and caused the French to retreat in chaos. The French troops saw it coming -- they were about to be outflanked and slaughtered by the Prussians.