Much Ado About Nothing and Grand Magic at Stratford
I do think something is lost by having Hero remove her veil earlier. Claudio's error is that he allows the slightest scent of tainted reputation turn him entirely against Hero, without pausing to consider whether the accusation fits with what else he knows of Hero or to investigate further. The fact that he agrees to marry the "cousin" sight unseen, without any knowledge of her reputation (or any conditions whatsoever), shows that he has gone past his prior condemnatory way of thinking. In fact, it enacts exactly what Abram's dialogue tries to add: "bringing Claudio to a point of openness to figuring out how to make love work whatever the details of their respective pasts." Though he knows nothing of this cousin, he does not try to negotiate or carve out exceptions--he will penitently accept her whoever she be. And, of course, she turns out to be Hero, so by submitting to his matrimonial penance Claudio symbolically reneges on his right to condemn Hero.
I don't know if that's enough to make Hero's psychology play out realistically without alterations, but I do think it's important to Claudio's growth. I respectfully suggest that the veil should stay on.