Like @mcarrico wrote, it's really annoying to have to delete and replace tools from the Reporting palette. Given how much nesting and daisy-chaining of tools it takes to get a good looking output, it becomes a chore when an change needs to be made early in the workflow.
I agree with this request. Or perhaps as an alternative, provide an option to turn off warnings for missing fields. I think from a user experience/ gamification /ocd POV, having something that throws hundreds of errors throughout my workflow when I make small changes near the beginning creates a level of anxiety and creates a sense that something was done wrong. It also makes it hard to differentiate from errors that I may want to address.
Please add this feature to the tool. It's been 3+ years when it was originally requested. It’s a big pain to remove missing columns by selecting each tool.
It's especially important for transparency and reliability of workflows. Most of the time we need to keep the warnings present, but if we want someone else to use your workflow, it's really important that there are no 'missing field' errors for them to worry about