Well, with the existing sensors there is no way that I think they'll ever allow anything where you weren't required to be watching the car. The sensors just are not precise enough. They don't detect everything they need to detect to safely do much more than it does now. And there's basically no way it would ever be able to detect something like your son's bike situation.
So, honestly, I think this is probably as good as it gets for summon with the current hardware. Much more and Tesla's really going to open themselves up to significant liability concerns. Maybe they're prepared to do that, but I doubt it.
And just like autopilot/autosteer, I think they're going to just start tightening/crippling features (like the recent +5 MPH rule and now the hold the button rule or whatever it turns into) vs significant improvements from here on until the next generation sensors are released.