My software development generally consists of:

C++  : high-performance code -- rendering, physics, complex
computations,
       system API calls (e.g. Direct3D)

lua  : in-application scripting

ruby : outside-application scripting -- building, generating C++ code,
       generating lua code, running tests, running benchmarks,
       everything else

The only reasons for using lua are sheer technical ones: effortless
portability (100% ANSI C -- especially needed for embedded platforms),
thread-safety, and speed.

What is absolutely needed in the game software industry is a better
lua.  My preference would be an ANSI C version of ruby.  Many things
would become easier if I could replace lua with ruby --- I would get
some synergy between my in-application code and outside-application
code, for example.  (I could of course use lua instead of ruby, but
that turns out to be more inefficient; besides, lua is generally
frustrating compared to ruby.)

So, what is standing in the way of an ANSI-C ruby?  How much of ruby
or ruby2 would need to be redesigned or changed in order to get a
streamlined, minimal ANSI-C-only version?