Walkie-Talkie - The Ultimate Phone Experience?

The trouble with smart phones is that its hard to input text. I seem to be especially bad at this.
First on Android, and now iOS, they have built-in a microphone button on the on-screen keyboard to enable voice-to-text (dictation). I think this is the future I want to live in, but the thing is, I'm not very good at this dictating either.

I wonder if future generations will become very good at dictating or if its so socially unacceptable that our race is destined to be typing on these screens forever.

In any event, my issue with this voice-to-text button on the keyboard is that its buried on the keyboard. What I really want is something I can do without looking at the screen at all.  Like "touch-typing" on a keyboard.

For instance, in the car, I can't afford to look down at my phone. And don't even get me started on our Ford Escape with Microsoft Sync...

Anyway, it turns out that holding the iPhone button to get to Apple's Siri gets me 'close' to what I want, but I think there's lots of room for improvement. I don't want to hold the button for a second before I can start talking. And I don't want Siri to listen for a while until she thinks I'm done...only to tell me that my request didn't make sense to her.

On my friend's new Android, the phone is "always listening".  This is kinda cool (and kind of creepy), but you need to wake it up by saying something like "OK Google" which makes you feel a bit ridiculous in public (and maybe even in private).

On my ideal phone, I would instead have a physical button on the side that is devoted to voice input.  This button would work like a walkie-talkie (or, perhaps less antiquated, something like that Sprint/Nextel "push to talk" feature).  Only, instead of talking to a friend or a group of co-workers, I would push the button to talk to my digital assistant on the phone (Siri or Google Now). When I push the button, the phone listens.  When I release the button, the phone stops listening. Its that simple. Why has no one done this?!

Aside from the physical button, I think we need all-around better conversational AI (or even just better screen-reader technology).  Its really sad to me that GOOG-411 was actually better for in-car use that my JellyBean Android phone.

First one to make a phone like this will get my $.
*kshhhhh* Over *kshhhhh*