If i plan to invest in icc, i always read their whitepaper because it is a great opportunity to find answers to all your question about the project. Then i always analyze their team and roadmap.
You're right this method's the best way to find the deficiencies and advantages of the ICO in question. But we mustn't ignore the quality of the team and their reputation because these two things often get the main spotlight from a number of people including investors.