Thought Tracker makes a good point about simplicity and productivity:
The bigger the language (syn)tax is, the bigger will be the distance to the Domain. (read: you will have more syntax-noise in the code). This "noise" can help you to understand the tehnology, but it troubles you in understanding the domain. That's why Smalltalk was good: very simple syntax. The rest was/is Domain Language.
This is one of the reasons I consistently harp on the complexity of Java and C# - they add capability by larding on more syntax, due to the inherent weakness of their original designs. Generics? In Smalltalk, we don't really have to think too deeply about the problem - unlimited polymorphism and DNU handlers gives us all we need, without having to learn a bunch of extra language rules. The Java guys spent years pondering the question, and then larded on syntax. MS didn't spend the same amount of ponder time, but they also larded on syntax.
Every time that happens, it gets harder to solve the actual problem at hand - because you have to learn the extra stuff they layered on instead of just diving into it.