I'd agree that the long sword is one of the best weapons.
As for the switch axe, there's no defense on the switch axe, either, so it shares some of the disadvantages of the long sword while lacking it's speed. In either mode, it is much faster and far less cumbersome than the Great Sword or Hammer; and in axe mode, it has far greater range than either, which is great for attacking groups of monsters. It's also nice because you can briefly switch from the axe to the sword for more focused, swifter attacks on a single enemy.
I've also found the axe to be fairly powerful compared to similarly-leveled weapons of other types. I think the Long Sword still comes out on top in offensive power simply because successive spirit combos can deal devastating punishment.