Since I started this thread I thought I would mention the actual experience.
Despite the extremely restrictive policies on Alitalia's web site, in my experience they were not enforced. the four legs of my travel on Alitalia were all on larger jets with plenty of overhead space. Many passengers had roller bags, and many had a second smaller bag as well, despite the restriction of 1 carry on. From what I could see anything that would have passed on a normal Delta flight would have been fine.
I assume some of their planes are smaller and have limited overhead, so it could be some flights this could still be an issue. The experience on their airline was pleasant and professional.
On a personal note, my first trip to europe was terrific. I found Florence and Tuscany very interesting, delightful, beautiful, and the people wonderful. I look forward to returning.
Glad to learn that you enjoyed your trip to Europe. It's hard not like like Florence and Tuscany.
You're right, the airline policies are rarely enforced but once in a while they are.