We decided to have no volume cap so that anyone willing can participate. We believe that if more people have AE the value of the underlying system will increase. No cap was also Ethereum's approach and that was quite successful.
By putting no cap on the crowdsale you are essentially putting the investors at risk. It's like a crowdfunding campaign without goal or telling the investors "I don't care, just give me all your money". I understand that you want to raise as much as possible, but I really hope you will reconsider your decision on this.