The Share widget in WAB is very powerful. I love how it can embed a query in the URL to zoom right to a parcel by address or PIN for example.
It can remember current extent. However, could it have the added option, underneath that, to also remember what layers are turned on in the layer list?
(even better, icing on the cake, would be if it remember what layers were added in via the Add Data widget. That would be neat but that would be much less important than just remembering what layers were on from the default service from the original webmap)