That's paradox - people without deep knowledge about finances and economics earning big money in crypto world. And I see little hate from people wo are working with stock markets towards to Bitcoin traders. People who studied for years and working it that sphere for many years can't understand how with amateur knowledge and not professional desicions can make more money than these who are working full time job with stock markets.
Ok, my minds about your question. I love to answer "what if?" questions
1. Regulation of Bitcoin isn't really possible. But things around Bitcoin are already strictly regulated. Exchaging Bitcoin to USD requires to provide all personal details, ID. Don't forget about capital gain taxes.
Ban of Bitcoin in USA? Is it at least minimal possibility that may happen? But if it happen, yes, it would have terrible impact to Bitcoin, much biggern than ban of Bitcoin in China.
2. It already happens periodically. And it have impact only in short term. Just remember what happened when btc-e was closed by US authorities. And we can't compary any of current exchanges with Mt.Gox. Mt.Gox had huge dominance in market and volume. Now everything diversified between many exchanges, so 1 or 2 fraud exchange wouldn't have huge negative impact.
3. Well, governments are already trying to make their cryptocurrencies. Question what people prefer - decentralized Bitcoin or currency controled by government. Anyway, both currencies can be popular at same time - like Bitcoin and all altcoins now.
4. It's a serious problem. It already happens sometimes that we need days to get transaction confirmed, especially when spam attack happens. But weeks - you exaggeratated it a bit
5. Looks that you don't know how mining works - mining difficulty will just adjust to the current hashrate.
C'mon dude, we are already in reality. Do you really thinking that every Bitcoin investor is an idiot with purple glasses who don't have critical thinking. You are wrong.