Instead of nullifying all spells only, the bard can either CHANNEL it at a foe to stop all their spells from being cast (single target) or otherwise it allows the bard to mask their sounds so that they are able to stay hidden while renewing songs. Hence, the Bard is now capable of being an ambusher, which though expensive may become an invaluable aid for many bards.

If keeping the same spell option, perhaps an EVOCATION retains the current effect.