A bitcoin options exchange needs to be very well trusted, which you are not. It would also need to be very well funded to protect itself against defaults by traders so it can keep traders "whole" when they have a profitable trade.
It would be a much better idea to start a reputable exchange and then expand into options trading instead of getting directly into options trading.
Our risk is the same as a normal exchange because we currently support binary options only. Users' maximum loss can be determined beforehand and thus can be fully covered by margin. Therefore there is no need to worry about defaults by traders.