The real problem, IMO, is that it's got some kind of closed-source licensing model. That may work for Microsoft, but not too many other people can get away with it IMO.
I used rebol 10 years ago and left it after few years because of it's closeness and artificial limitations set. The general closeness was a huge factor IMHO.
I'm back now. With direct communication between community members and REBOL author the feel of closeness is gone now even in R2 (also free versions of R2 can talk to dll/so -s now also which was the main hurdle back then).
R3 is about to fix the things discovered wrong in R2. It's development is highly interviewed with community. With very active development chat, open buglists, wiki based documentation, weekly releases, autor's blogposts that ask for opinions I can say the closeness factor isn't there any more.
I am not sure but I think in R3 everything except very narrow core of language will be open sourced.
"I am not sure but I think in R3 everything except very narrow core of language will be open sourced."
I am not sure if that would be very attractive to hackers. Why would anyone want to use a non open source language these days? Making a language closed source (even in parts) these days is to guarantee that it remains a niche language (unless it has been lucky enough to have a lot of pervasive legacy code, which Rebol certainly doesn't).
I, for one, would never choose a closed source language for one of my projects.
