Select field for refer lookup fields

Select field for refer lookup fields

Hi,
I don't remember which version it came in but I see that we now are able to create additional fields that refer to other tables (Users, Technicians, Vendors etc.) natively in the Additional Fields configuration. 
I have started to test this in some of our templates but have run into an annoying limitation. 
Referring to Users specifically in my case, but I can see this being an issue for other tables as well; Since we are only able to see the "Full Name" field from the Users teble in the template we have an issue selecting the correct user if there are several users with the same first and last name.
I would like to suggest that we are able to choose which fields from the Users table to show in the lookup field in the tamplate. For example, show email address instead of (or in combination with) Full name. I know how to get around it, I have used refer fields before using FaFR.
It's just a suggestion for future improvements.