Quark and Rom's...I don't see a single dead parent as laziness, that reads more to me as just saying 'oh their parents are dead' and not describing them. Moogie is clearly fleshed out and Quark and Rom's father is definitely mentioned enough to get an idea that he was a traditional ferengi and influenced Quark a lot, to the point that Rom is clearly the mama's boy and Quark takes after his dad.
I got the impression that Quark's father was a traditional-thinking Ferengi, but that he was also a total doormat.
Quark believes himself to be 100% the spitting image of his idealized father (in denial about his father's shortcomings), but he's really a male version of his strong mother, holding the beliefs and ideals of his father.
Rom is more likely the basic embodiment of their father, but he shares the beliefs of his mother.
Quark treats his brother Rom like dirt and doesn't realize that it's almost the same thing as treating his beloved father like dirt, because he can't see his father for who he was (he sees Rom clearly enough), and because his father would've wholeheartedly endorsed treating someone as "weak" as himself like dirt. Quark's father never stood up for himself (much to Moogi's chagrin) because he knew he deserved what life threw at him. And on the rare occasions when Quark recognized failure in his father, he was able to blame it on Moogi's unwanted help.