I had replaced a stamped wing with a white oak framed slab of 3/4" MDF on one of my saws. It served me for years and served my dad for nearly as many. Sure its not CI but, it certainly works.
Actually Glenn is being too conservative. He did a beautiful job. The wing was a good as a good commercial cast iron wing and a whale of a lot better than most commercial wings or any pressed steel wings. Let me see if I have a picture of it. Yep, I do. It is attached.
The wing was perfectly smooth. Wood slid easily on it. I kept it waxed with Johnson's Paste Wax (Johnson's Non-Skid floor wax comes in a can that looks exactly like the wax used for tools, cars, etc. It has been around since I was a child). The oak strip was only on the end that abutted the table saw top. As you can see in the pic the other edges were buck naked with a 45* bevel to prevent edge chipping. The pic is when we first set the wing up in my shop. A bit later, to replace the temporary leg, a cabinet was built underneath the wing.
I used the wing for several years with zero complaints---until I got a new saw.
As soon as I saw Carol's thread I was going to post to tell her about Glenn's wings. Oh yes, the wings looked great. I forget how he finished them, however it really worked well and looked good too.