So many Walls have "defender and flying." So how do they differentiate among the "defender and flying" Walls? Mostly through power and toughness! Apparently, an Angelic Wall is not as strong as a Wall of Air, and Wall of Air can actually hurt meek little 1/1s.
However, some Walls have more depth. And that's where I want to help. I don't want swords to be defined as being simply 3/5 as compared to a Hover Barrier's 0/6. I want the swords to actually mean something.
So, obviously, I chose first strike. But why did I keep the other two abilities? Because I couldn't remove them. All Walls, by default, have defender. And these swords are up in the air! They're flying swords! Alas, I was stuck with either changing the power and toughness or adding more rules text.
Lastly, I could have changed this to be an instant or sorcery, but it LOOKED more like a Wall. But I can see an argument for how this is a temporary instant/sorcery effect of a "wall of swords."