But isn't Wildedge's attack just counted as one even though it hits everything? There is Asura Priest. But even with half shut or impenetrable attack, it might be dangerous because of the low attack.
...No card works that way. There is no card in the game that can declare more than 1 attack at a time. (And it would be dumb if there was.) Wildedge's effect is identical to Asura Priest, Machine Lord Ur, Berserk Dragon and Grasschopper's.
There are monsters that can attack more than once per turn, but each attack is treated as a separate attack. You can't declare just 1 attack to destroy all your opponent's monsters.