In my opinion it is really dangerous to start restricting creativity on a artist's forum. I think so long as it is within the general forum rules (no pornography etc) artists should have the freedom that they choose. And if the challenger does not accept the challenge then they just decline to participate.
The whole reason I come to draw on these boards is to exercise my creativity. It should be a liberation not an incarceration.
Pummel: 8 Wins. 7 Losses.
I think it's fun, and very acceptable for street fights since those terms can be negotiated and agreed upon. But I think for ranked matches, it's best to keep things simple to allow artists to spread their wings and do what they want to do within a subject as simple as "spiderman" or "wonderwoman". Then let creativity run wild.
CrazyD, keep in mind that we're all pretty reasonable (for the most part) here. It would have to be pretty intentionally extreme to raise eyebrows. People would be having to go out of their way to be jerks about the topics they're choosing for it to be an issue.