The possibility of Bard being implemented means we're likely finally going to get a definitive answer on exactly what Larian plans to do with reactions. A lot is at stake here.
Don't know if it's the best thread to ask... but what's the main appeal/features of Bards in D&D?
Speaking as someone that is currently playing a Valor Bard in tabletop...
You take Bard for their sheer versatility. They won't top the damage charts, but they are damn good at enabling everyone else to do whatever they need to do, and are extremely good at skill checks themselves, especially of the charisma-based variety. When I was playing BG3 using the Bard mod, pretty much every persuasion check only needed a 3 or higher to pass. They are also full spellcasters, though they don't have very many direct offense spells compared to the other casters. They do have almost every utility-based and mind-based spell under the sun, though. For one, they're the only class in the game with natural access to Speak With Dead, Speak With Animals, and Speak With Plants, along with all of the language-related spells.
All Bards share 1 main feature, Bardic Inspiration. As a bonus action, Bards can give a Bardic Inspiration die to a party member, who can then use it to increase an attack roll, ability check, or saving throw result by 1d6 (which increases by a further d2 every few levels). This stacks with stuff like Guidance too. Note that in most cases, the Bard cannot use the Bardic Inspiration die to influence their own rolls. The amount of bardic inspiration die that a Bard can give before needing to long rest is based on their Charisma modifier (although they get restored on a short rest at level 5, which makes them extremely spammable afterwards). This mechanic is PRECISELY why there needs to be a proper reaction system, as you can only use it for one effect before the die disappears.
The Bard subclasses generally add additional ways to use the Bardic Inspiration die. So let's look at the features of the two subclasses we're most likely to get, Lore and Valor.
College of Lore: The subclass for Bards that want to focus more on the utility/casting side of the class, as well as hindering enemies.
+ Ability to use Cutting Words as a reaction, which lets them use their Bardic Inspiration to instead lower an enemy's attack roll or ability check result. Enemies cannot even roll a saving throw to resist this.
+ At level 6, Lore Bards can learn 2 spells of any class, as long as they are capable of casting them with an appropriate spell slot.
(Note that all Bards are able to do this at level 10 as well, Lore Bards just get an additional 2 spells much earlier. This can also lead to things like Bards learning what are normally Ranger and Paladin exclusive spells far earlier than they do, though it's unlikely BG3 may take this into consideration based on what the level cap is, because there'd be no reason to implement spells like Destructive Wave if a Paladin can't get to level 17 to begin with.)
+ At level 14, Lore Bards can use a Bardic Inspiration die for their own ability checks.
College of Valor: The subclass for Bards that want to focus on combat and further supporting party members.
+ Bonus proficiency with medium armor, shields, and martial weapons
+ Bardic Inspiration is upgraded to Combat Inspiration, which allows a character to additionally roll the Bardic Inspiration die towards weapon damage rolls or AC against an incoming attack.
+ At level 6, Valor Bards gain the ability to Extra Attack.
+ At level 14, Valor Bards gain the ability to use a weapon attack as a bonus action after casting a Bard spell as their main action.
So basically, I'd argue that Bard might actually be the best class for a main character to have in a game like BG3, if your primary goal is to see as many dialogue options and pass as many skill checks as you can, and they absolutely aren't bad at combat at all.
