A few days ago, the player Camaranth started a thread on the tank forums examining the number of tank swap mechanics in raids. While the discussion is a good one, there's a reply written by Snuzzle not far down the thread with an interesting observation. "I think the reason we are seeing so many encounters designed with tank swaps in Mists," he/she writes, "is that fights are being designed with Raid Finder in mind ... They need both tanks to have a job to do. Tank swaps are the way to do that (because) most everyone can instantly understand (them)."
LFR might not be the only reason for that, but I think Snuzzle has a point. Encounters have to be programmed with the knowledge that Raid Finder groups will always have two tanks, 6 healers, and 17 DPS, no guarantees on class composition, and the knowledge that coordination will realistically be minimal. I don't think it necessarily reflects on the skill of the players concerned so much as the inherent disorganization. Under the circumstances, it would be extremely difficult to program an encounter like, say, Kael'thas or Teron Gorefiend or High King Maulgar, and have it remain somewhat close to the normal and heroic versions.
I don't know whether LFR actually does have a serious impact on raid design, but it's certainly an interesting question. In related news, the LFR version of Siege of Orgrimmar was nerfed recently for reasons I think all of us can guess.