Laments about the "quality" of renders focus on a rather narrow and subjective view of what art should look like.  Complaining about this kind of thing has gone on for as long as people have created visual imagery.  Art is about evoking an emotion, inspiring thought or seeking change.

Maybe you're right that most of what gets posted here evokes, inspires or seeks nothing in particular.  Perhaps that's not what people are trying to do.  Poser is often about fantasy, so if you're looking for serious art, you'll have to wade through a lot of material before you'll find something that's even intended as seriously artistic.  That's the nature of the program. 

Robyn is right about a popular method of posting here, whereby a single V4 figure gets put into a new outfit, posed and rendered with glaring light as if it's "art."  Maybe it's appropriate to broadly dismiss people who use Poser as not serious, but like any other generalization, exceptions exist and it's not fair to those folk to presume that everyone who uses Poser is inferior artistically to those who are using higher-end software.

A group of people who haunt these forums complain endlessly about lighting, but a lot of us are simply doing the best we can.  Some folk are getting gradually and steadily better at making light in Poser appear like something that approaches what we see in real life.  If you're expert in that realm, I affirm and applaud you.

Meanwhile, I try to make every render better than the one before.  If that doesn't meet your standards, and if most of the people reading this think my gallery is lame, you can either help me improve what I'm doing, or ignore me as irrelevant and focus on what you feel is more important.

How does complaining help?