I'd suggest taking a run around the How Stuff Works article on LEGO manufacturing
Effectively, there are two types of mold, one designed as one-offs or limited runs (minifigs, special characters, etc), and one designed for much longer use (typical part molds or very frequently used shapes). This was the problem that led to the windscreen from the original UCS X-Wing never being made again in any other set... the short-term mold had degraded and couldn't be used even if a set could make use of it. Thus, when the new one came out, totally new part.
That being said, the mold isn't really at issue on something like this, it's more of a limited production run. LEGO is more than just the ABS and even the mold, it's also time on a production line, colors, quality control, etc. These are basically limited runs that are never intended to go into mass production as-is, so I wouldn't expect to see it exactly like it is.
Eventually, we'll see an Azog show, he is set up as a primary bad guy, after all, but it's more about where to fit him in the lineup and when to scale up production than a matter of mold choices.
If the above post didn't offend you, you're probably reading it wrong.