I personally feel like, if they can't produce a "replica" of the puppet due to the materials involved, don't create that character. At the very least, I'm not going to buy it. Can't make Gonzo's nose right, Don't make Gonzo. Can't make Piggies head right, Don't make piggie. Make Scooter, Make Rowlf, Make Beaker, etc. Essentially, make the characters that were primarily constructed of fur and fleece.
The only people that are going to shell out this kind of cash for these items are the hardcore people that hang out in places like this, so the "Secondary characters won't sell" argument doesn't hold much water. You're not going to sell it to a casual muppet fan at K-Mart. Anything less than a replica is a Doll. I don't need a $200 gonzo doll. When someone walks into my house, I want them to go "Hey, this guy has a real muppet" not "Hey, this guy has a life sized gonzo doll".
The only way we can keep the quality of these up, is a flat boycott of the ones that fall short. To me, animal looks "OK". With a little work, it will probably be spot on. Gonzo looks like a toy. And if you go and add a plastic palisades nose that some people are calling for, it's going to look even worse, because when someone looks at it without a direct reference, any kind of fabric solution may be passable, but they know his nose wasn't hard plastic.
I don't have a solution, other than, "don't make gonzo". Because if you make gonzo, and it looks like crap, I won't buy it. If gonzo looks like it does on Terry's myspace, I'd pay twice as much for it.