And the new costumes haven;t messed up the old design.
Lis Sladen had said they were the ones she most wanted back for SJA ("They were the only monsters that looked good from the back as well") but knew she wouldn't get them till after Doctor Who had paid to build the new costumes...
PS: Havign said that, they are a bit boring aside from the great design, just an amalgam of several obvious Who tropes: warlike aliens+shapeshift and replace humans+own planet destroyed and need another one+origin of a great Earth legend. So basicalkly, the sort of enemy the Doctor knocks off when he wants a quiet afternoon, and likely to only be the catspaw for the real villain.