Common Warstriders didn't even exist until recently. During the First Age all Warstriders were made from High Magitech. During the harsh centuries since the Great Contagion when so many Factory Cathedrals and workshops have been lost and jade is in short supply, people, usually in the Threshold, have to resort to more primitive expediencies to construct these monsters. Only the underlying Essence powered systems are constructed from jade- with the rest of the machine covered in steel. Such makeshift workmanship would be viewed as utterly vulgar in the Realm but in the Threshold fielding a Warstrider of any description is enough to make an impression. Hence the Realm's introduction of the derogatory name 'Common Warstrider' for those built in the barbarian lands as opposed to the 'Noble Warstriders' piloted by Dynasts.
Point of Reference: compare the original suit in Iron Man to Tony Stark's factory build model.
