Well yeah. Starlark and sandboxing are the best things about Bazel, but it could still definitely be improved. So I'm still curious about other build systems.
I think making a new build system without sandboxing (or at least a plan for it) would be pretty stupid.
I want to introduce Windows sandboxing, too, but I'm not as confident about how to do that: https://github.com/256lights/zb/issues/31