The default delimited log file definitions are quite restrictive and limit what we can do when importing more complex log files and information. The Message Tracking Logs from Exchange overruns the available options for Fields quite quickly and there are many places where we would want to use lookup text, far grater than the default of 8. There are more text fields in that log file than there are available text inputs, in particular for length of strings.
Additionally there are some logs and other sources of information where we would need to add groupings and support for nested data. The Exchange tracking logs have a few places where data is sub divided beyond the comma with a semi colon to break down even more data (recipients etc). Another area where this would be useful is importing from PowerShell and being able to absorb objects and columnize/nest the data.