One issue I see with Bards as just that class: would they use an entirely new 'weapon' type, an instrument? After DHs I'd be really against that. Or would the instrument just be customization, technically a doodad like Outlaw's Pistol, only showing for certain skills, while regular combat uses regular weapon types?
Also, it's not a new idea, but what if "Bard" (fighting musician) and "Tinker" (uses lasers and deploys turrets) were two specs of the same class? Mostly linked by the tangential use of ranged weapons, as the game definitely needs more users of these items.
Bundled together because they are concepts where there are difficulties finding distinct specs, but the ideas are interesting, and a one-spec class would be shit.