I'd love to see Lookup fields. A use case example:
I work with a lot of freelancers regularly and poll them for their availability for the various projects I work on.
I get their ability by posting a form and emailing a link. Naturally their responses are returned to a list.
I'd then want to be able to extract their contact details from a master "Freelancers" contact list, and "merge" this via a lookup into the availability responses list.
So, in this case, one of the Form entries is "Name" and this name field could look up the name in the Freelancer Master Contact List.
This enables me to manage just one master contact list, but for the relevant contacts to automatically populate the lists where that person pops up.
For my workflow, I provide a viewing link to the production manager who is going to actually book the staff based on their availability.
Combined with the lookup functionality I'd be able to easily give the PM's a quick and easy chart to see who is available when, and their details to make the booking.
Many thanks for your time.