The sigil thing is definitively a bikeshed. For one thing besides Python I don't don't know why you consider that JS, Java or C# don't use many sigils, these languages just happen not to have C-style pointers so they don't need that particular bit of syntax.
More generally using C-style syntax means that C and C++ coders will be at home, while people from other languages will have to familiarize themselves with the concept anyway, sigil or not.
Beyond that, I don't think I've seen any serious study on the acceptable level of sigils to maximize productivity and readability in source code, as far as I can tell it's really just a matter of opinion. Personally I'd take C syntax over Python every day of the month, and I've written quite a bit of Python. My only sigil-related problem with C is that '->' should really just be '.' IMO.
There's was a talk at StrangeLoop a few years back about a language syntax being designed based on user feedback from its ongoing usability studies. I'm on my phone now, but I'll try to find and post the link later when I'm at my computer if someone else doesn't find it first.
More generally using C-style syntax means that C and C++ coders will be at home, while people from other languages will have to familiarize themselves with the concept anyway, sigil or not.
Beyond that, I don't think I've seen any serious study on the acceptable level of sigils to maximize productivity and readability in source code, as far as I can tell it's really just a matter of opinion. Personally I'd take C syntax over Python every day of the month, and I've written quite a bit of Python. My only sigil-related problem with C is that '->' should really just be '.' IMO.