[cliffu]

I started out writing disagreements to your points, somehow having misread them as being arguments you support for Rubists preferring dynamic typing, but then during editing I re-read that you think it's productive in spite of dynamic types. I agree totally.

I don't think Java-style typing is that much of a hindrance. It's irritating boilerplate, but people using those languages can slam it out very quickly.

I don't think reasoning about runtime types is any more difficult than reasoning about compile-time times, it's in fact a higher cognitive load because you cannot ignore it and rely on a type-checking phase that covers all your paths without explicit test cases.

I personally found Ruby to be productive[1] due to the expressive metaprogramming, how easy it is to make DSLs, blocks and yield for CPS, generators, and co-routines, and how everything is re-definable. I don't know how much dynamic typing factors into that, but I think if you could get the same things with equally expressive syntax, Rubists would still like it.

[1] It used to be my favorite. I still like it (and love it for scripting), but prefer GADTs and pattern-matching on type constructors now.