Balkanisation of Ruby?
When I first started using Ruby, Matz's C-Ruby was mostly the only game in town.
I am also an enthusiastic user Ruby 1.9.x, JRuby, and MacRuby. Seeing the Ruby spec being developed in Japan under government funding, and that it is for Ruby 1.8.7, I get a feeling of déjà vu as a long time Lisp user.
The balkanisation of Lisp has been more than a small nuisance for me in the last 25 years. I would prefer that all Ruby implementations eventually implement a common specification, but I would rather it be for something that looks like 1.9.x.