At a high level, FME can very simply allow for user input. I build workspaces all the time for clients with multiple user parameters as input.
Same goes for output or you can hard code the output to be based on the input as you stated.
To quote from the FME Desktop training manual:
Successfully translating from one format to another requires a firm grasp on all the parameters that control the translation.
Parameters are what control a translation. Chef Bimm says… “Parameters in a translation are like the options when you order a coffee. You get to choose what ingredients you start with,how they are combined, and what the end result of the process will be like. And I think both coffee and data are better when you add a whipped cream topping!”
So coming to your question of making your FME Workspaces interactive to the users, yes it is very much possible to the highest possible degree even without a drop of coding knowledge"
In the hierarchy of different translation components, each different level of the hierarchy has a set of parameters that belong to it.
So there are: Workspace Parameters Reader Parameters Writer Parameters Feature Type Parameters Format Attributes (Feature Parameters)
Having parameters right down to the feature level provides a huge degree of control over every aspect of a translation.
Hope this helps.
Happy FME :-)
Cheers
SRG
...and if you are still doing research on this. Take a look on FMEPedia for the terms "Generic" and "Dynamic", where Generic refers to the data format and Dynamic refers to the data schema. To summarise then if a workspace uses a Generic format on the Reader and Writer and it is in Dynamic mode, then you could theoretically put pass any data through it and carry out a process like data validation on it without the process needing to know what format you have at run time or what format you want out and also it doesn't need to know your data's schema in advance. This then decouples the data from the process, throw in parameters as mentioned by SRG and you can then control the process. So FME allows you to write code, without having to write code using the Workbench GUI.