I think your last 3 points stem from point #2 which is the main root problem.

One way to solve it, which is too flawed for me to actually suggest it, would be to add a rule like You may not upload your own art. This communicates unambiguously that e6 is not a personal gallery. It would stop many complaints about uploads not getting approved. And people would be forced not to take it personally since their uploads can't be their own art. The rule wouldn't actually be enforced, of course, it's basically just a deterrent for complaints.

The obvious downside is that there are artists who do upload quality art to e6, sometimes with better quality than elsewhere, and that's great! That should be encouraged not stopped. So I don't think this is actually a good addition to the rules overall. But it would address a particular issue we have.