Normal BW logfiles include a header for every log, giving details like channel, requester id etc.. This is very useful for having an overview of where to start troubleshooting, you don’t need to spend time looking for the details in the log body when you troubleshoot.
ECS logs does not include this information, here you have to go through the body for to get the same information. This slows down troubleshooting.
Use of centralized ECS logs with BW logs header would give the best of both worlds.