Steve Yegge has a long post up on the topic of "the next big programming language". The title of this post comes from this assertion:
Rule #1: C-like syntax
C(++)-like syntax is the standard. Your language's popularity will fall off as a direct function of how far you deviate from it.
There's plenty of wiggle room in the way you define classes and other OOP constructs, but you'll need to stick fairly closely to the basic control-flow constructs, arithmetic expressions and operators, and the use of curly-braces for delimiting blocks and function bodies.
Probably true, regardless of how much I think that cripples a language. For instance: C style syntax pretty much guarantees that you won't have named arguments. Instead of something readable like this:
webServer startOnPort: 80 maximumNumberOfInstances: 10 usingHostName: 'www.somehosthere.com'.
No, instead you'll see this:
web_server.start (80, 10, "somehosthere.com");
Which is a sad commentary on the industry, but that's the way it is. Meanwhile, at least things are iterating in the direction of the trail Smalltalk blazed decades ago.