Any fatalities is bad. But, from 60 unaccounted for to 1 is a huge relief assuming the information is accurate. A good night to give your kids an extra hug.
There are some initial technical notes in some pilot forums that seem to indicate some changes to the landing threshold in terms of how the pilots are guided to land. Way too early to tell what the cause is and many different factors possible.
In the end, if only 2 people lost their lives in a crash where the entire tail section ripped off, I’d say Boeing put together a pretty good airplane.