In specific, the subrecord testing was rather interesting; the vanilla CS will load and save an unknown subrecord without any fuss. TES4Edit will fuss about an unknown subrecord, but will still save it just fine.
So if you move your esp changes to an entirely new subrecord (perhaps with the OBME identifier), players will be able to still edit the plugin in the vanilla CS, TES4Edit, etc. Would be more work for you to move the data field around, but I think it'd be worth it for compatibility with TES4Edit.