Roethlisberger has been a shell of himself for a few years now. Nothing changes between this game and the first one next year. If the rivalry is diminished because Ben retires, then it's already happened. I don't think it diminishes one bit because of Roethlisberger. He's had a great career, but he has been pretty bad for a while. If you thought this year or last year's or two year's ago games meant something, then so will next year. All the rivalry loses when Ben retires is nostalgia. QB play for them probably improves next year compared to recent years, unless they don't try to address the position in any way.
I agree the rivalry has been diminishing a little bit every time one of the big guys on both teams retired. Ray, Reed, Ngata, Bart Scott, Ward......they all were part of it. But there was still a little bit of the intense emotion as long as there was still one guy left. The rivalry the last few years wasn't close to what it was around 2010, but fans in Baltimore still had Roethlisburger to hate.
I'm not the only one saying it. They were saying it early this morning on the WBAL pre-game show, they just had a great piece on ESPN that featured Ray Lewis, Terrell Suggs, Bart Scott and Haloti Ngata. And of course Rex Ryan is on ESPN so he had a lot to say about it. Sure it's always going to be a rivalry, they are division rivals. But players make rivalry's special and Ben Roethlisburger just represents the end of an era when both teams had a number of hall of famers and both were considered the cream of the AFC along with Indy and New England. Both teams will have good players again, but it's hard to see both teams having as many great players at the same time the way they did in the late 2000's and early 2010's. And players that represented the toughness of the two cities the way the Ravens and Steelers did. At least not for a while anyway.
It's only my opinion, and it's not an opinion shared by everybody, but I'm also not alone in that opinion.