It would be nice to have the ability to load a dataset to ArcGIS Online and have the ability to turn fields on/off. Useful where I want to create a service for Desktop viewing, querying, and filtering of the data, all of the data. Once I have what I want, I could turn fields off for a specific map for field collection where I only show fields that will be edited in the field. I would end up with one layer with different ways to utilize the one layer, whether I am using Dashboard, JS Viewer, or a mobile client. The data is updated on one dataset.