Bards are a rather uncommon class to see in videogames. You'll see them in some turn-based RPGs where they generally aren't all that popular, but you'll pretty much never see them in action-RPGs. Let's change that.
I imagine our class as a 90s kid with baggy pants and a backwards cap, carrying an oversized boombox. His weapons of choice would be gauntlets, leggings and beatboxes, and generally his attacks would derive from
Capoeira. When a battle starts, the Beat Boxer would set down his boombox somewhere, which would show a ring or a sphere indicating the radius of its effect. If the Beat Boxer, for instance, put on
Fire Water Burn, all fire-based attacks within the radius would grow stronger, whether from friend or foe. In addition, the Boxer's own attacks would gain fire properties, being able to ignite things and dealing extra fire damage in general.
Here's the gimmick: Setting down a boombox would make a timer bar appear on the player's HUD. The interface would look similar to something one might see in Guitar Hero, and the idea is to activate various attacks and block in time with the bar. As you accurately time your attacks, the passive buff grows stronger. More successes means the radius and the effect of the buff increases. The moves need to be performed within the radius, as well. There's also an immediate effect for each correctly timed move, in that the fire effect would be stronger on hits where you hit accurately and perhaps nonexistent on moves where you completely missed the mark. These effects would synergetically grow stronger over time as well due to being affected by the passive buffs. Perhaps blocking in time with the music could unleash fire-based counter-attacks.
One could throw out a thousand ideas for this class. Maybe the class would be partially controller by automation, allowing the player to focus on timing using a Guitar Hero controller. A few flicks here and there could change targets and throw out the boombox at appropriate times. Maybe the timer bar would require you to use specific abilities at specific times. The player could set up which button corresponds to which ability, and through memorising songs they like playing they could plan out which buttons need to be moves that regenerate MP so that he doesn't run out of energy mid-song and which buttons there are a lot of so he could put low-cost abilities on them.
It could also be cool element to include in multiclassing. Why not play as a spellsword, setting your sword on fire through magic while throwing down a boombox playing
Poison? You'll vomit damage over time everywhere through stylish sword-dancing!
Or maybe through through infusing your weapon with lightning and setting your boombox to music from The Dark Knight Rises you get an electric guitar that shoots bats.