It would be easier to track if data loads are correct and if transformations are not messing something up. It would be good to know how many rows are coming from extraction, how much from data load and how much is landing in Process Mining. Have that information in logs would allow to compare between different loads and thus spotting issues with data quite easy.
During extraction phase we would like to have:
number of tables which are extracted,
names of tables which are extracted,
number of rows per table which are extracted,
live summary what is extracted - how many rows for which tables, which tables are in progress, which tables are done,
expected total number of rows for every table which will be extracted.