(Note: I'm kicking off this discussion with a conclusion from an otherwise outdated thread, circa 2020.)
Having had a fair amount of time to reflect on the evolution of things, I think we need to make undecorated word fetches not produce an error with NULL. I've outlined the history of why they were erroring at the outset, and walking through it I think there's a coherent plan for when there is tolerance and when there is not (e.g. function arguments by default).
But today I realized something particularly pleasing about this. We had a concept that BLANK!...due to its non-erroring status, would be the way of "disarming" a null assignment to a variable. It's still going to be a way of disarming parameters for "blank in, null out", but not needed for a plain assignment.
That frees up blank for dialect uses distinct from NULL.
In particular, it recovers it for something that was tried for a time... being synonymous with space (
#" "). The concept emerged when it was called into question whether PRINT should default to adding implicit spaces, and how you should avoid it doing so. print ["It" _ was _ "ugly"] if the common case didn't have implicit spaces, so ultimately we went with SPACED by default and you could write print unspaced [...] if that's what you wanted.
_was deemed to need to behave just as NULL did, as you couldn't put a NULL in a variable. So when you needed to, you would use blank, and it would be the non-erroring synonym. It was a sad loss for when you wanted a nice way to note spaces, but seemed to be the way it had to be.
Well, not any more!
With non-erroring NULLs, dialects are free to distinguish the behavior of blanks and nulls. NULL being the most obvious "nothing". So why not bring back BLANK! as being a synonym for space?
It still has the "no delimiters applied" status of a CHAR!. So spaced ["a" _ _ "b"] would still be just two spaces between the a and the b... not five.