JSON has one glaring flaw: nested json encoding in strings becomes awful to read. I encounter it too often in reality where individual layers use JSON, but want to support arbitrary strings in their API. Encodings which use prefix length don't suffer from this, which ironically even includes most binary formats.
Back to my main point though: normally I don't need the complexity that things like nested JSON would be. When you do though JSon is a bad format. (actually I would go so far as to say you never need something that complex - but the problems you are trying to solve with nested JSON are still complex enough that you should use a more powerful/complex framework, but better design of your data store would avoid the need for nested JSON.)
