if you want to set up an exchange have these three things

1. get the licences / regulation requirements fr dealing with large amounts of fiat
2 have alot of your own investment in the project EG paying for licences yourself
3. set up the code to be secure and reliable to do many many trades per millisecond.

WHY you may ask?
1. it shows your within the law so fincen cant shut you down for breaking the law
EG don't be dumb working from china accepting dollar for instance, thinking they are immune due to foreign location
EG don't avoid regulation thinking that its regulation that gets your bank closed (actual fact its lack of meeting regulation that gets bank accounts closed)

2. having a lot of money shows that (A)you are good at money management. (B) more positive signs that you probably have experience in Forex markets to know what your doing professionally

3. nice code that works well will get you great reputation as a stable service and many people will trade with you.

for all those guys with just 4BTC to their name thinking that they can be the next billionaires by starting up an exchange. forget about it, do something small scale like trading locally, using OTC.

we don't need run of the mill script kiddies opening 300 clones of MTGOX for just 1BTC worth of labour and domain registration, We need proper forex experienced coders with large investments to do the job right, and then set up multiple branches where each bitcoin/FIAT is based on average incomes of the locations not based purely off of a central exchange price.