We know, you cannot get informed of every single trade made because of the P2P architecture. But you can still use the exchange if there are enough trades that you are informed of!
What problem you are actually wanting to solve? I don't see why I would use a slower system. waiting can be very costly if the price is moving against you. you need quick traders to provide liquidity. which is what you will find if you get users onto such a system. the high volume traders won't like it. I think there is actually room to reinvent the worldwide exchange system.