In some people's view, that would be ethically acceptable and everything else would be corruption. I think it would be plain idiocy, waste, submission to someone's opportunistic logic, and ethics have nothing to do with it. Ethics work both ways, you know. Whenever they don't, one side of the story must be hypocritical. I'm all for the designers making money, but there's a difference between doing business as usual and laying the law for the hunt.
Most derivative works have a utilatarian end.
People don't add another engine to their lawnmowers if their lawnmowers were satisfactory to them. This is probably the biggest double-standard around. If Bitstream or Adobe or URW were to do derivative work, it's reproduction with improvement in mind, but if WSI or Brendel were to do derivative work, then it's highway robbery. If people have objections to what Andre did, let someone speak with enough justification to their objections. A link to TypeRight and a shadow of legal canines are not enough.