>>>SO, We can say that the monitoring of IFlow does not cover all the functionality to monitoring message than Business Process Engine
CCBPM and Iflow.. they are completely two different things and you cannot compare them.
>>>I will create an Example but its not clear for me, in case of error in a mapping step (simple mapping or multimapping), how to get the structures involved to analyze them and see what is happening
If you enable the logging, you can see the corresponding mapping name under the audit log. So if a message fails, you can go to ESR and find that mapping and test it with corresponding payload.
It's not difficult to find the mapping even if you don't enable the logging.
By looking at any message, you can get the interface details such as sender system/Interface name.
we can find the relevant ICo with a simple search