Are you used to 3rd edition/Pathfinder? One of the things 5e did was nerf a lot of "force multiplier" type abilities. Bards still have access to some good CC, and Dissident Whispers is a force multiplier since it triggers opportunity attacks by your mates. And you should get to pick spells from any class list at level 10/6 depending on subclass. That's assuming this ability works in BG3.
But obviously, what a bard does in a fight is hit people with a lute.
