What I'd like to see is primarily better communication and release
management. Communication would not just apply to Ruby developers
announcing changes early on but also discussing them with the teams of
the various Ruby implementations. This already happens to a certain
degree but the recent outcry of refinements shows it can be greatly
improved.

One thing I'd like to see is a website of some sort that shows the
various internal aspects of Ruby such as how code such as `*numbers,
number = 10, 20` is handled, how one should implement refinements, etc.
Whenever MRI (or some other Ruby implementation) comes up with a new
feature that affects the syntax, parsing or similar stages this website
would be updated accordingly. In my opinion this would make it a lot
easier to make their own Ruby implementations, code that parses Ruby
code and the likes without having to dig through the C code of MRI.

Release management is another important factor. Ruby 2.0 is closing in
on us and while the version number would imply it potentially contains
non backwards compatible changes (if one were to stick to semantic
versioning) this doesn't seem to be the case. What I, and probably
others fear is that Ruby 2.1 will be a release similar to Ruby 1.9.1.

Yorick