This is important because it is an integral part to the story, the wings are a biological part of the flock, they don't need flashy thrusters or metallic wings to kick butt. Eagle wings also just look so much more majestic and bad-ass than some fancy dancy metallic wings. Finally it is just not canon to have eagle wings in the books, and metallic jet wings in the comics. If it aint broke don't fix it, keep the flock classic and original. The people have spoken, and we have chosen to speak against the mech wings.