All of the alien races kind of remind me of Christians. There's some moral imperative towards some type of desired behaviour, and this behaviour is difficult to maintain, so people do all kinds of stupid bullshit and simply claim that they are honourable, logical, holy despite their regular actions to the contrary.
Considering that Star Trek chronicles the story of military crews, it makes sense that you would see a disproportionately large number of disreputable aliens.
I personally think it would be cool to watch a series based on normal Klingons, living their lives as doctors, priests, etc, going about their religious, social, and economic life. But I can see why many people might find it boring.