Its awesome. The problem is that only specific types are supported by a bunch of these types of libraries. In the case of gopy you cannot do anything with a nested slices in structs which limits things a bit.
Yes this is definitely a little limiting. I'm also experimenting with a slightly different binding method, where passing pointers to structs is disallowed (gobind currently allows pointers to structs). All structs are only passed by value, which solves a lot of the underlying problems and allows for slices and nested structs. I'll have something tangible in a few weeks and might switch out the dependency on gobind.
EDIT: edited for clarity