This is one of the great features that I use all the time (and I am so glad many of the things I really wanted eventually made it into the design). The one thing that would really supercharge this is the ability to create and select display templates for the mention. Right now clicking the db icon lets us change the fields that are to be shown (which applies everywhere there is a mention):
However, if you could define the display templates at the db configuration page and use this menu to select a template, that would really be great (e.g like this):
There would be a default but the user has the ability use a different style/template to show different fields. One use case for this is including people/contacts. There are places where you just want to mention the person’s name (default case) but there are instances where you might want to also display their title and company (e.g. a bullet list of contacts). It would be very helpful to be able to just simply select a different display template in those instances.
In line with the other discussion in this thread, it would be amazing if you were able to include entities as blocks/cards within rich text & documents (see also Inline reference - card view also the process flow described here). I think this is really the most viable option for embedding rich-text fields from entities into documents: