When calling the task xForm, the URL includes both a participant Token and a user parameters.
Why do we need to specify the user, when we can have him/her from the participant Token ?

Need to check on that one.
It was more or less going to do the same answer as the task type, but maybe this could be removed.
Need to check with the people developing custom form managers.

You have any proposal ?

There have been a few questions on this forum about the underlying use or purpose of particular data elements (which have been answered probably more than once by busy people with important day jobs like yourself). How about dedicating a bit of time to documenting the metadata alongside the architecture?

You will probably find that the participant token is better regarded as a transient piece of security and system management data for active instances and the user name as a piece of business data. Repeatedly calling on tokenservice to display the user name may not be a smart idea and if these tokens are ever managed out of the bpms then you will lose a piece of business data about the process.

David