Bard the Bowman. Obviously Bard the Bowman is strictly better in Multiplayer. But no review still seems odd to me. He's not always the best. His stats could be more streamlined, and his ability could be economically abusable like generating cards, resources or actions.
But Bard the Bowcannon is a special character in the lore. How many other characters can boast to have slain a dragon? Not just slain, but shot out of the air, and killed, with a single arrow. The Black Arrow. Tales of dragon slaying usually don't talk about the third age, in which all the well known characters live. Bilbo and Thorin Oakenshield have passed through Esgaroth at the long lake before enraging Smaug the dragon. Bard the Cannonman didn't provoke the dragon's wrath. Yet, still, the dragon came and spit fire upon the laketown, and Bard the Mancannon had to deal with it. He had to rally the townspeople, against a dragon, and you can see his town burning in the background of his card art. He didn't falter, nor did he run.
Did the fellowship stand their ground against Durin's Bane, the balrog in the mines of moria? No, they fled. And while it is arguable whether a dragon or a balrog is more powerful, or harder to kill, or whether that specific balrog or that specific dragon are stronger than the average of their kind, it is still true that Gandalf, one of the more powerful beings in middle earth, fought the Balrog for 10 days. Bard the apex of Mankind only needed one arrow to slay the last known living dragon.