FIXED in 10.9.3: OS X File System Hang Bug
Hooray!
As far as I can determine, the OS X File System Hang Bug has been fixed in OS X 10.9.3. While my bug report has not been updated to reflect the fix, I have yet to see the issue resurface in 10.9.3.
Update: premature: the bug might not be fixed after all, given user reports.
However, Apple developer support tells me that the bug is NOT fixed in 10.9.x (but to be fixed in 10.10 Yosemite), so the workaround of disabling file system journaling is still a wise precaution when testing drives.