The new College of Dance Bard subclass looks like it will be really fun. Unarmed strikes whose damage scales with Bardic Inspiration dice and uses Dex. Unarmored Defense that adds Charisma. Bonus action unarmed strikes when you use Bardic Inspiration.
You get to be 3/4 of a Monk, but also be a Face, and also be a full caster, and also get half proficiency in everything. And then the level six stuff buffs your party’s initiative and movement to the point it’ll be very hard to get the drop on you.
A fantastic new subclass all around.
I think it would be just as viable as Monk up in the front lines. As a lvl 4 monk, you’ve probably got 18 Dex and 14ish Wis. That’s AC 16. Dance Bard will have 14ish Dex and 18 Cha, so also AC 16. Same d8 hit die as Monk, too.