I also ran into these issues when I integrated Slack and Monday.
If I make a pulse or update from Slack, I want to be able to mention my coworker who it might be relevant to while creating it.
As for being able to assign a person - we have an “Employee Tasks” board, where my pinned view is filtered to only show me things assigned to me. I want to be able to assign it to myself during creation in Slack, so that when I go back to my Employee Tasks board, it shows up right in my view and I don’t have to hunt for it.
It would also be great if I had the ability to set the values of various columns of the new pulse from Slack (such as due date and the Status column we use for project categories, since my boss prefers us to set those things at item creation as well), but I get if that’s harder or makes the UI more complicated.