A reputation system will be needed because as the identity is known to the other party (bank details) there will follow by itself a reputation system if we dont install it. Users would start to blacklist scammers in forums or make false accusations.
But its another challenge to build a solid reputation system.
Hey k99
Have you had an opportunity to take a look at bitcoin-otc "Web of Trust". It has been running smoothly for some time so it's something it's worth checking. This web of trust has supported trades without collaterals, so I guess it's going to be good enough for your enhanced system that includes collaterals and game-theory to enforce that traders stick to the initial contract.
Yes the Web of Trust seems to work pretty good in practice.
We will update soon the concept with escrow and some reputation system included.