Default log behaviour should be useful, easy-to-read with maximum information and minimal waste lines

This is a generic point which I'm hoping can be considered/discussed separately from specific issues I'm about to raise on (default) logs that bst currently generates.

In part this is because it may be that some of the following issues could lead to "that can be done via configuration. closed" which may or may not be a good outcome, depending on whether the default is 'better' than the non-default configuration.