It's probably not. Restarts (and similar) just seemed like a really useful tool for use in production environments. Anything that makes error handling more powerful, flexible, or understandable is a good thing. But changing arc to support it might be a bit much, at least at this point.
I do think it would be good if we could improve arc's error handling though. Or at least error reporting on the repl.
Arc doesn't have hierarchical dynamic typing like that...
I had created a hierarchical typing system for arc once, by just changing the tagged symbol to a list of symbols that is treated as the type hierarchy, but I think I lost the code... I'll have to see if I can find it.