So basically like a localbitcoins.com 2.0. It would work in a similar way, with some additional features but the main difference is that it would support not only bitcoin, but a few other cryptocurrencies as well, like 7-8 currencies, the most established ones.
Do you see a demand for such platform? Would you use it?
LocalBitcoins is not exactly a peer-peer network,it does act as a third party between all the peers for verification and validation.Most of all,they have control of your money that is not what a p2p network does.Localbitcoins doesn't supply any currencies,all the trades are initiated by the peers.
Basically,you have got it all wrong.You should google what a p2p network is and maybe reframe your idea.