Harry Mudd in TOS was a more delicious living source of trouble than Dirgo...of course, he was made for comedy and not drama.You can imagine that, in-universe, there was much more too him, but making Wes look good while making things difficult for Wes was his only purpose in the story. Everything he did or asserted in the story was wrong. It was even his dangerously-rigged shuttle that got them into their situation in the first place. He was the object lesson in "what not to do".
It would have been more interresting if the mining conflict had been the subject of the episode and not only the pretext for a crash in desert. Picard and Wesley have trouble during the negociation while the Enterprise is attacked by one of the groups involved in the conflict. We could have seen more about the not utopian life of the miners.