It is a bit on the simple side, however there are two reasons for this. First is that, its a wall. Walls are functional, they may contain some decor, yet on the whole it only makes repairs expensive. And in this case, the decor it has is in the architecture, not necessarily the materials used.
The second reason is the the original purpose of this design is for the massivecraft server, where elven decorative materials like quartz are rather on the rare/expensive side. Far more expedient to spend these materials on the primary area of the fortress then on the mere outer walls. A server-based version of the previous reason.

Also, you can't exactly say its really a strict human design, and even less of an orc one. It looks more elven then anything else.