Add a small field [250-500?] in all transformers for a description. Make it part of the summary annotation.
One of the features I love about FME is the ability to label on the 'map'- workspace. I don't have to go to another document to read about the process. This would enhance that ability.
Its not always ideal to describe everything 'on-screen' and a lot of annotations can make things messy.
Another option could be to make annotations collapsible. This would help clear up some of the messy mapping but you could still have a 'large' description handy without taking up real estate. - I saw this was another suggestion.