We are using Sitecore 8.2 update-5 along with corresponding wffm module. Form submit action 'Create Item' doesn't show any way to configure item's name. is there any way to set it to one of the form's fields?
I'm afraid that is not possible out-of-the-box.
What I can suggest is that you create a custom
<item:created> event handler to rename an item of your certain WFFM item template.
That would work as a dirty fix.