Yes the reason for this is in its design. Banshee has this constant movement to it which makes it more difficult to just stay afloat and shoot someone, then move out of the way if you have to. Also the projectiles are slower plasma ones.
The problem with the wasp isn’t just durability but its entire mechanic is that its an easy to use, annoying to counter, one person vehicle that has access to what are practically hit-scan machine guns and superior unrestricted movement.
Whereas most other vehicles in Halo are either “coop vehicles” like the Warthog, requiring multiple people. Single-seat vehicles, balanced by its movement or weaponry like the Banshee or Ghost, or it’s a vehicle that’s a powerhouse with just one person inside because its either of the tanks.
Now redesigning the Wasp is probably not a very likely thing to happen, but like you said making it easier to take down, imo basically making it out of paper considering the effective range and movement it has, would be a good way to balance it.