Most important hurdle for any exchange right now is trust and security... Right now most people don't trust any exchanges because of gox,vircurex,cryptorush,poloniex,coinmarket.io...etc. If we can prove that customer can trust our exchange with out any doubt, then we won half the battle... Is our exchange 100% secure...? Can we guarantee the customers that, we never lose their coins....?
Further to this, it's also important to prove solvency. This is a must for exchanges now:
https://iwilcox.me.uk/2014/proving-bitcoin-reserves