> I think everyone would prefer if apple split it into the 'Messages' app (SMS + RCS) and an optional 'iMessage' app which doesn't come installed by default, but you can download on the app store from Apple.

No, I don't think anyone would prefer that. People on iOS like iMessage, not SMS + RCS. Nobody is confused by it, they all know that green bubbles means you're texting someone who doesn't have an iPhone. It works seamlessly, it's just annoying when you want to have along conversation with a friend on Android because it doesn't have any nice iMessage extras available – that's why people don't like green bubbles.