I'm not saying how the parameters or return values should be formatted other than the fact they're in JSON format. JSON-RPC requires you to conform to their specifications.
APIs that ignore the realities of distributed computing and that each have different special-snowflake wire formats requiring tedious documentation: the worst of both worlds.
Your post implies a pseudo-free-for-all and defeats the purpose of having a conversation about a standard exchange format.
You basically have said "I want to make it work the way I want it and I don't care if it's non-standard and unintuitive.". You're welcome to do that, but everyone who needs to work with it will hate you. And when you've been working on it for 2 months, or take a two month break, you'll come back and hate yourself too...