Deaths / Deaths + Recoveries gives a 5.7% death rate. Obviously there are mild cases that are never diagnosed, but it seems if you get sick enough for a confirmed diagnosis, your risk is higher than generally reported.
The problem here is, from what doctors seem to be saying, there's a massive amount of the population that has or has had COVID-19 and will never know - since the symptoms in an otherwise healthy adult are similar to the common Flu. So that death rate is likely far, far lower than what it seems. The flu kills between 15-60k people in the US every year, and it's around 1% fatality rate (and nobody seems overly concerne…
The undetected case issue can be addressed by intensively studying smaller populations and extrapolating to the general population. The Diamond Princess or other cases where every person in a defined population was tested and monitored would be a good place to start. The exponential growth issue can be solved with cohort analysis, group people by the date of their onset of symptoms and track the resolution for each group.
With a few more weeks of data we should start to see these studies, then we'll know just how serious this is.