Allow the creation of feature layers using a schema builder similar to Microsoft's SharePoint list wizard. You would pick the geometry type (point/line/polygon) then add attributes. Based on the data type like Text, Pick List, Number, Date, Yes/No, etc you would have other setup options. The user would define the pick list domain values, any default values, decimals places and min/max values for numbers, date vs date/time. Include calculated fields based on other attributes. For example, a user inputs a "inspection date" and the calculated field adds 7 days and auto-inputs the "follow-up date". Include system attributes like lat,lon for points, length for lines, area & perimeter for polygons. These attrubutes could be greyed out or hidden. Customize the data input forms (order, format, etc) using the builder or the existing pop-up configuration tools. These adhoc features layers would be useful for quick inspections using Collector. The web map could be authored using operational data as the background then layer these editable features on top. The adhoc features could be consumed into ArcMap like any hosted service or exported from Portal/AGOL as Shapefiles.