Print Engine 2 Layout not showing legends for user-added Shapefiles

With the old Print Engine 1, PDFs created from Print Templates in VS Web included legends for user-added Shapefiles. This no longer occurs with Print Engine 2 layouts. I understand that the new Print engine relies upon the base web map from Web so the printing service isn't aware of user-added files. This has a significant impact on many of our 2500 users who often want to add shapefiles received from external colleagues or contractors to their maps. 

I understand that this isn't easy to resolve within the new setup but in my opinion including a legend for your data is a basic mapping requirement and this was a feature present with Print Layouts and Print Engine 1. Enabling users as publishers in AGOL would be a nightmare for management of content so isn't possible in our situation. 

Is there anything on the Web/Printing road map that will resolve our issue? Thanks.

We use the VS Web and Printing SAAS products with AGOL only.