I was holding off on Pitts because I knew it would be one of the toughest of the bunch , but I don't see many flaws in yours. I also would love to leave Bradshaw off but it's impossible in the hearts of Steeler fans.
I would say Swann has a place in the discussion at least - argue all day about whether he was overrated or not but he was a very important Steeler.
Same could be said about Franco Harris.
I might put Woodson on there just because he really deserves it , he was that fucking good. I'd take Noll off to do it. Also it would help represent another era.