In most rpgs, bards are not an option. In rpgs with bards as an option, there are no rpg elements that give the bard some much needed flavour.

Some choices and outcomes should be unique to bards. "The bard alone could hear the distinctive hum of the buried translucent crystal sword echanted as to vibrate to the sweet tones of music or oratory performances. In the bards hand it was a formidable weapon bridging the flows of music and combat..." There are weapons like this in d&d tailored to bards in the source materials.

Bards in BG3 will hopefully have unique flavorful dialogue encounters, nice audio and animation for musical skills and some nice bard-specific equipment from the equipment supplementary books that make them feel like d&d bards.