Thanks, Marc! By "context", I meant What is the `Scheme community', and how does RnRS fit in? In more detail:
I think anyone who wants a fast Scheme compiler ought to use Gambit. That's what Brad told me a long time ago, and I'm sure it's true. So it doesn't matter to me what the other Scheme compilers are doing, because I won't use them! So I wonder why you even care what other Scheme folks are up to, what standards they're proposing. The obvious answer is that you & Gambit belong to the `Scheme community', and it's important for the community to embrace a good standard. But I really don't know anything about this community. That is, how are schemers and compilers connected to each other? If the connections are weak enough, who needs standards? Shriram K (whose book I improved, finding & fixing an error on free/bound variables) made a good relevant point: We don't think of TcL and Python as being the same language, even though they're similar. They go their separate ways.
Let me tell the sort of answers I'm thinking of. I belong to the Pure Math community (even though they haven't hired for 10+ years), which maintains lots of Math journals, and it's the joint responsibility of the Math community to maintain these journals at a high quality: to publish true & useful results. All the referees, editors and theorem-provers work together, depending on each other, connected.
Now I use Scheme to write programs, as I find it a pleasant language to write in, and Gambit is acceptably fast, but I got into Scheme mostly because of the slogan that Scheme is a good first language. Well, you don't need a Scheme standard for teaching a CS101 class!
I stuck around in Scheme because I got interested in some CS points: Felleisen's Lambda-value Calculus (LC_v), and Denotational Semantics (DS), which is promoted in Clinger's R5RS appendix. I think LC_v and DS are fascinating mathematical subjects, but I was very baffled by the response I got. I simplified some of Felleisen's LC_v results (better Y_v combinator derivation, shorter proof of the Standard Reduction Theorem), and Felleisen didn't care, he didn't merge my improvements into his manuscript (which Flatt now maintains). I concluded that that CS students aren't expected to understand LC_v, but to be properly intimidated by it, and then go on to more useful endeavors. So I have no feel for how LC_v (or LC) fits into CS. Clinger disgraced himself on comp.lang.scheme by failing to understand the simple mathematical points I was making about DS: we can easily define compositional semantic functions without the use of non-Hausdorff Cantor sets (i.e. Scott models of LC). I concluded that understanding DS is also not important in CS!
OK. I know that Clinger and Flatt are involved in R6RS, and I find them baffling. What (little) I know of their CS interests doesn't explain to me why they're interested in Scheme, still less why they should be trusted with a Scheme standard. That is, suppose instead that LC_v & DS were vibrant CS pursuits with strong connections to Scheme. I think I'd see why CS professors like Clinger and Flatt were involved with the Scheme standard.
Well, there's also applications, right? Is Scheme supposed to be a good language to write real-world programs in? Telecommunications software, video games? If so, presumably the folks who write these real-world Scheme programs have a real need for a good standard. But I don't know who these folks are, or what their needs are.