Thanks for the introduction!
(Sorry for delay in reply. I'm traveling, in Charleston 
at the moment, so programming is a bit on the back burner right now.)
Since you mention Wasm, I assume you've seen the 2019 conference videos...
Chasing native platforms (and native GUI) is really tough. Red has a hard time not being flagged as a virus...and now I'm stuck with a lot of trouble of the evolving TLS cipher suites. Although we can try and justify work on any problem with dialects, you spend a lot of time on make-work, and there is only so much time in a low-bus-factor project.
I've been saying Wasm is the main focus of Ren-C. But I definitely do have the same reluctance that any of us old people feel about abandoning "the dream" of a cross-platform tiny binary that can still build with minimum dependencies, and yet be the only tool you need on Windows/Mac/Linux/wherever.
So I'm a bit better at saying that I only care about Wasm than I am about actually being laser-focused on delivering a minimum viable product on the platform. 
This is one of the things I may have to come to term with after this vacation.
I like building "time-traveling artifacts": things you can run in emulators that could have worked on machines of the past, had the code been beamed back in time.
Some people like Kaj are even making Atari 2600 a "first target". (That's not the weirdest thing about Kaj; I'm down with with making an Atari dev tool--just accompanying it with manifestos proclaiming yourself a great disruptor and innovator is... 
)
So I am mindful of "can this work on old machines". I've grafted Rust features onto C: in a way that modern C++ (C++11) compilers can verify... but old C compilers can still compile (C89 plus variadic macros...some pre-C99 compilers could do that).
JSON was inspired by Rebol (maybe helping stop XML will be Rebol's final legacy, I dunno).
But it is interesting to see that Rebol wound up not measuring up. I dunno if you saw Carl's ASON idea, which is a bit of an oddity... born we must assume from the frustration of "why did JSON win". But among the things that he wanted to go back on was braces for strings.
Don't know how closely you've followed the decision-making here, but... Ren-C has introduced FENCE! as a new list type, and taken on --[dashed bracketed strings]--.
Anyway... I'm one of Rebol's biggest critics. At first it struck me as "just another interpreted language, with weak semantics and infinite failure modes". Then I started thinking "well... what if you wanted to program like this: how would you make it work?" Then I got invested in arguing with people and the rest is history.
Well don't be afraid to post here on things you want to talk about. My main focus is on binding and the language model to try and get it to "work".
Beyond some interesting implementation details, the big distinguishing factors of Ren-C are probably isotopes and rethinking the binding model:
There's a lot of other stuff that's "cool" and fun to talk about. But those are at the core of what's really different here.
