Q: What is your scenario related to forms?
A: I would like to create a set of forms in one site and then utilize them in another site with the Forms page widget. I would expect this to work as follows... First, you go to the Manage Sites link in the upper left corner (part of the multi-site module). Second, I would click on the actions menu of the site I wanted to share the form with and click Configure Modules. Third, I would click the change link under the section "This site can use data from..." for the forms module. Fourth, I would check the site I want to use forms from. At that point when you visit the forms module you would see the sources section and you could choose which source you want to view the forms from. In the forms page widget you would then be able to change the source of which form you want to display on the page.
Q: What do you expect to be shared between sites?
A: I would expect the form to be shared and I would expect the form responses to follow them automatically. Although it may be nice to also share form responses separately as I assume there could be a scenario for that as well. Also, You should be able to share or not share form fields across sites. For example, we may have a lot of form widgets in one site for a specific purpose, but in a lot of other sites they would not be needed.
Q: Do you expect to see form responses per site?
A: I think it would be nice to be able to pull form responses from another site independent of the form itself. However, the form itself and its content would be managed in the site it was originally created in.