I really don't know, since I have no real understand of global economics.
I don't quite follow the reasoning of cheap American goods -> exodus of capital.
I really agree with you. That is why deflation is scary, it will likely lead to hyper-inflation.
Of course, it is true that hyper-inflation, if it happens, will happen quickly. People will be, as you say, hoarding their cash because of uncertainty. But when they become confident enough to borrow from the banks again, and the large reserves they have been stockpiling hit the fan, it is quite possible that people will quickly notice the change in money supply, and react by trying to get rid of their money too. Which would set off hyper-inflation. But this hyper-inflation is not caused by deflation, but rather by inflation, which people may not notice because of their presently high hoarding rate.
1) That purchasing power went somewhere. Instead of going to what people wanted, though, it will have gone to what the politicians want, which is most likely a waste of resources. At the very best, the investments will be mostly harmless.
2) It doesn't just cause the exodus of capital, it practically is the exodus of capital: by printing money, they devalue all of the cash investments in the United States, thus reducing the amount of investable funds. While the foreign capital may be able to buy more dollars worth of goods per euro, there would be far less local capital to be invested.
3) While in theory the lower value of the dollar would make purchasing American goods more attractive to foreigners, that is often not the case. Just because a currency is cheap doesn't mean that items denominated in that currency are cheap. One example of this which I have experienced recently is the East Carribean Union dollar, which is worth much less than a US$, but where all of the items cost as much or more than they do here. Just because the currency is low in value doesn't mean that goods are actually cheap. Prices can rise to make up the difference, and often do.
However, if the dollar becomes cheaper not due to inflation, but because of our continued trade imbalance then yes, your description of increased exports would be quite accurate. Trade imbalances aren't bad, and they can't last forever. What goes in must come out or accumulate. And in the case of dollars, accumulation causes a relative change in value. Supply and demand and whatnot.
4) Extreme inflation can cause instability, and reduce investor interest. No one wants to invest in Zimbabwe, because they are financially (and in other ways as well) unstable. Inflation is bad because it throws the future into question, and makes people less likely to lend money. If they do it is often at a higher interest rate.
Also, deflation is not nearly as bad as many people think. Yes, dramatic and sudden deflation is just as bad for an economy as dramatic and sudden inflation. But an economy can get used to deflation just as well as it can adjust to inflation. In fact, it is almost a bonus, because it encourages saving, and thus investment and growth. I'm not saying that we should intentionally cause deflation, just that it's not a guaranteed cause of a death-spiral. The United States had a long deflationary period in the 1800s, and it was also one of the longer periods of high sustained growth. This will not always be the case, but there is little reason to be more afraid of deflation than inflation.