The idea seems entirely feasible.
The idea doesn't seem feasible at all unless you solve for sybill attacks and if you could do that you wouldn't need mining to begin with.
In an anonymous network you don't really think it would be brain dead easy to make a 1 PH/s farm look like 1,000 1TH/s rigs do you (or 1 million 1 GH/s rigs)?
I don't know, that's why I asked if there was information I was missing out on. It would certainly make it harder for a miner to dominate a coin.
So why not solve for Sybil attacks? And how do you mean you wouldn't need mining? If you can prevent somebody from running a thousand miners with the same IP address, how does that mean you don't need mining?
Everything can't be done, until it can.