I like your thinking about possible safety avenues, but I'm not sure any of them have any real merit.
Regarding toddlers sticking metal objects into the socket, the 2008 National Electric Code calls for tamper proof outlets, which are already adopted by an overwhelming majority of states. Those are fairly cheap and prevent sticking items in one side of the socket. GFCIs have been around for quite a while that trip if it detects a slight imbalance in electric flow, sending the current through a relay which cuts the power.
I don't see how and outlet could logically not allow current t o flow if it risks overloading the circuit since it would need to have the draw first to determine that. Isn't this what circuit breakers are traditionally for? Implementing that in an outlet would seem to be like a GFCI where it trips that outlet but leaves the circuit functional. I'm pretty sure voltage would require the device to be smarter, not the outlet.
Grounding on an outlet (the third prong) is only good for protecting equipment, not people. Again, the device would be able to make that determination if its smart enough, the outlet has no practical way of enforcing that without being able to tell a smart device to actually flow current through ground and then sense it for verification. An outlet on its own can't do it, and assuming both outlets and devices were changed to support it, said device would then trip a GFCI if it wasn't plugged into one of these special outlets.