So based on all these examples, {moch Qel} *could* mean
"higher-rank-doctor", but maybe not.

So it leads back to the next question if that always works, or if it's
only acceptable if Maltz says so, or if there is a pattern. It seems to
work with all materials, and I guess all of the other examples can also
be expanded.

The genitive is ubiquitous throughout all of Klingon. The pattern is quite clear. I only gave a handful of examples; there are tons more. I can't see any serious argument being made that the genitive noun-noun construction is an insufficiently documented grammatical feature of the language to employ it in daily use.

That's not to say there can't be exceptions. For instance, Klingon from the Sakrej region do not use the noun-noun construction with area-nouns and pronouns as other Klingons do. Where most Klingons say jIH 'em for area behind me, Sakrej Klingons say 'emwIj. But these are exceptions that prove the rule. The fact that the Sakrej usage is an exception means it's an exception to the general rule of the noun-noun construction.

-- 
SuStel
http://trimboli.name