I often encounter the same problem and need: I want to add text input in my workspace for various reasons. You could use standard transformers for this task, as AttributeManager or AttributeFilter, but I think a new type of transformer would be more appropriate. I give you the most common scenario:
You want to filter out certain id:s (perhaps from a long list or a database) to try your methodology. The id:s could be found elsewhere and you just want to copy and paste them in your workspace and then hit Run. Let's say that you have 10 or 20 id:s you want to check.
The new transformer, called TextInput or something else, would look something like a merge between a standard tranformer and an annotation. You could just click the annotation area and paste your text and it will automatically be put as the attribute fme_text_input.
The only parameter for this transformer would be a checkbox if you want the textinput to be transformed in to a list and a choice which delimiter that should be used for creating this list.
