"Well, one of the reasons I was interested in compiling at least the standard arc library was for improving startup speed, say for use as a simple cgi script on a shared host, or a basic command line utility."
Oh! That's what you're talking about! Sure, I've experimented with that too. I think it's possible, but it would require mucking about with Racket's code loader... still, that's not a bad idea.
"I suppose its possible that trying to add fexprs to arc would just make things worse, but I was always attracted to the idea of making environments and scope easier to manipulate, and macros fit in better. As it currently is, macros are very separate from the rest of the language and stick out a little bit. I've rarely had a really good reason to need it, but it just bothers me sometimes that they aren't first class citizens."
Absolutely. I too like the idea of fexprs. I'm just saying that from a purely practical perspective, Arc was not designed around fexprs, so tacking them on after the fact won't work so well. It shouldn't be hard to make a variant of Arc that is built around fexprs. In fact, wart is very Arc-like but has fexprs (or something that's like fexprs anyways).