What are the most obvious flaws that would need to be corrected?
One of the many things I learned in life is that as long as anything is made by man, it can not be perfect and even if one can be flawless there will always be kinks especially in the implementation stage where human nature and different situations can crop in. The same is true with blockchain and cryptocurrency. But don't me wrong because blockchain is definitely revolutionary in itself but how we are going to utilize it with real-life challenges can be a little bit different of a story. I am not so sure what you mean that Bitcoin surpassed PayPal...can you please elaborate on that. There are many strengths as well as weaknesses of Bitcoin and we know what are these things...just use Google and you can see what I mean. One, there remains to be a big problem with scalability and the speed of transactions but I am expecting these bottlenecks can slowly be eased soon. Second, it is taking a lot of power for mining Bitcoin and this is a major concern with green minded people. Many are saying that Bitcoin is not actually the best blockchain but there is no question that it is the pioneer and so far the leading one.