What really sells models is presentation and top quality renders

That's probably true if the final purpose is for still images used for visualisation work. I don't have too much experience with rigging & character animation, but odd triangulation may cause issues.

It could be dangerous though to allow models with flaws onto the marketplace, as being an experienced photoshop user myself I know how easy it is to retouch out geometry errors. If sellers do any retouching to their presentation renders (ie photo filters, adjustememt layers etc) they should say so in the description. All of my renders are as they come straight out of vRay.

The more information a customer has, like lots of different angles & wireframe renders the more likely they are to buy in my opinion.

Yes your are 100 percent right 3dcn bad geometry is terrible when it comes to organic rigging. So when people create characters they have to be careful especially around the joints.

Yes having multiple renders using wire-frame is a great way to help buyers determine the quality of the geometry.

I noticed that on CGT starting pages only really high quality rendered models show up.

You never see any really cool original low poly or high end game art.

It is nice that they sometimes put up some cool 3D prints but they seem to promote art that is technically great but lacks true originality because it is a perfect reproduction of someone else s work.