Jackson-based layouts have few options and users have little control when configuring them.
Json format is widely used in the industry by log aggregators like logstash or datadog yet the lack of control pushes users to other solutions like https://github.com/vy/log4j2-logstash-layout#usage which might not be easy to find or trust.
At the very least, the pattern for throwables could be used, but there are many more possible improvements.
Ralph Goers: "I am not particularly happy with the JsonLayout at the moment as I think what it does is too limited. I'd like there to be a lot more flexibility as to what the resulting JSON should look like, not just dumping the log event."