Simple requests like those used to list hosts or servers shouldn't require messing around trying to keep up with the SubData Direct protocol. It should be easy, right?
Now, SubAPI includes methods simalar to those seen in SubServers.Bungee for accessing data for Hosts, Servers, SubServers, Proxies, & Players easily. Requests the SubData Packet API is already capable of making will be included as methods in these variables.
This is how SubServers will implement the Validator API that I suggested. I had to make some assumptions though (like how I don't expect BungeeCord's api to have a setTabValidator() method).