The biggest problem with these ideas is that json is already supported in the browser. There might be a use case where your data is better represented in LDIF

The biggest problem with these ideas is that json is already supported in the browser. There might be a use case where your data is better represented in LDIF because it's hierarchical, but there's no built in LDIF support, so now you're importing a ton-o-javascript just to parse some new format. At this point, we should realize json isn't meant to be human readable anyway. If you need to hunt through it, you put it into some type of json viewer so you can see the tree and query it. It's an interchange format, that's more compact than XML. If you're shipping data between non-browser things like backend services, there are already binary formats like protobuff that have typing and can be optimized for small payloads.