One problem of the criticism by Carl is, if people use Rebol as if it were another language. Then two things: Rebol can do it like that. It is unclear how to use Rebol in the mindset of the developer in question. Perhaps things are not explained well enough.
There are a few examples around, but not many well explained, or puzzling. Also 'dialecting' as a great power of Rebol, is showing up in a few examples, but very very few good are available to take as an example for own work.
GUI and VID are maybe such examples, but personally to me it is still a mystery on how the dialect is really working with the AGG in the background providing the coupling with the system/OS.
So just stating "Rebol dialects are the way to go" is like saying "look at that plane in the sky, here is some paper, sticks and glue, now make a plane so we can go on a school trip with it next week" to your kindergarden class. (Well maybe not the best analogy)