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.
Why do you think this is a problem? "Overbought" is a speculative term for day traders who want to sell ASAP, lol.
IMHO, if you truly believe in the project's potential you want as many other people to take part as possible for bigger network effect. Caps are like soft private sales - you restrict the number of potential backers and users in order to make 10 people rich. It's all in the family.
Waves is overbought, Lisk is overbought, I don't know how much Aeternity will raise, but what I confirm is over 10k btc is overbought, hope only 1-5000 btc so that investors can make money.