Here is my response.
1) What is your particular scenario related to duplicating forms?
We run promotions for our customers/dealers and in order for them to redeem for a promotion they need to fill out a redemption form which is just a Sitefinity form. For each of these promotions we need a new form, so it would be nice if we could duplicate an existing Sitefinity form and start modifying from there.
On top of that we sometimes create branded landing pages that could live on any one of our web sites. All of our sites exist in the multi-site module so it would be nice if I could share the form and form responses across different sites but still maintain the form in the original location where it was created.
2) What do you expect to be duplicated: form fields, form layout, form responses or all of them? Why?
I would expect form fields (and all controls in general) and form layout to be duplicated. I would not expect the form responses to be duplicated since you are technically creating a new form, but maybe it would be nice to have an additional option asking if you want to copy the form responses as well.
3) Do you want to be able to share a form between sites in order to use one and the same form in different sites or you just need to copy the form in order to reuse some of the fields and the layout?
If I share a form across different sites then I would expect the form to be the same and NOT just a copy of the form. Although it would be nice if I could duplicate (copy) a form to a different site. So the key here is SHARED versus COPY. SHARED implies the same form just available on another site and COPY implies the form was duplicated to create another instance of the form. I feel a good solution would deal with both scenarios.
4) If you have one form shared between sites how do you expect to see the form responses? Do you expect to see them per site?
I would say that it is the same form whether it is on site A or site B. In the same token I would expect to see all form responses whether they were submitted to site A or site B as the same since they where submitted via the same form. My expectations would not be that since I shared the form (same form instance) to another site that it would have a different result set, because again it is the same form.
If you wanted to see a separate set of form results then I would say you should duplicate (Copy) the form to the other site.
I also want to mention two other items that, in my opinion, would make the Sitefinity forms solution much more powerful and provide huge value to your customers. This includes...
Second, the ability to apply conditional logic to forms which would cause form fields to show or hide. For example, if I check a checkbox field it would cause a textbox field to display.
Hopefully this has been helpful. Thanks.