I guess some of my gripes about ASDL have to do with our tooling. For example I find it annoying that the 'kind' enums overlap, so if I have a void* that I know points to an AST node I can't look at the kind to tell what it is.

Anyway, regarding Pablo's proposal, I think that if we do it, we should do a full migration, not a piecemeal one. I think the vast majority of asdl_seq_GET calls are immediately preceded by a cast anyway, and the majority of asdl_seq_SET calls are in generated code.