I think that visually it would look better if new blades always appeared in what is now the fifth blade spot, and then moved into the other positions as more are summoned. So right now blades appear like so: 1 3 5 4 2. I would make the first blade appear in spot 5, then move to 3 while the second blade is forming; second blade would move to 4 after forming to look more balanced. Then third blade appears in the 5 spot. First and third blades move to 1 and 3 spots while the fourth blade is forming, then second and fourth blades move to 2 and 4 spots.
The blades should be removed visually when mounted and probably when out of combat for more than a few seconds.
Blades don't regen while mounted, which means that in a map like Drizzlewood, where there's usually one group moving between events via skyscale, you're not always starting the next fight with full blades, which seems to be the intent of the out of combat regen.
I am completely baffled by the lack of an off hand dagger.