Yes, this is possible. The completion of an envelope is not specifically dependent upon a Signature block. If can be any action including adding data to a text field or even a checkbox (if required). The fact is that you could literally create a Template with even an Optional field and then really each Recipient just clicks Finish. Envelope complete. I would recommend looking into using Supplements where the Recipient has to perform a View, Read or Accept action.

Also remember there are different Recipient Types...so if you created an envelope that was sent to one person and they were set to "Needs to View" that is all they need to do for the envelope to be considered complete.