I think that any new programming language must specifically address at least some of the modern software development challenges. For client-side languages those will be browser and mobile-device deployment, and for server-side languages (and, actually, for client-side as well) it's concurrency.
A possible marginal improvement in productivity just won't cut it. We need languages like Clojure and Erlang that help developers write software for the modern age.
This isn't specific to Redline, but do take a look at the RoarVM http://soft.vub.ac.be/~smarr/renaissance/ a many core research implementation of the Smalltalk VM that does some very interesting things with non-determinism. Also there are Javascript implementations of Smalltalk that run inside browsers like http://amber-lang.net/ although I haven't had the nerve to actually deploy code to users written in Amber.
A possible marginal improvement in productivity just won't cut it. We need languages like Clojure and Erlang that help developers write software for the modern age.