Your idea is quite interesting and I think, you are in a good starting point as you are already asking for other people's opinion to make it better. But one thing I'm not sure is this one:
The only fee charged would be a 0.1% withdrawal fee, all trading volume would be no-fee
I know that you're thinking that this would provide you some edge over the existing exchanges that we have right now but wouldn't this hurt your exchange itself? Where would you get your income to maintain this exchange if you wouldn't get no fee from all the trading volume that it would deliver?