Also, if rift did just stop doing raids it wouldn't survive as f2p because the majority of people are here for the PVE. I think they know that. If they were going to stop making raids they would probably also close down the game and save themselves the money.
Yeah, I don't see the raids stopping should the game change business models. However, I can see them putting a bit more emphasis on open world Rift content though, as it's much more accessible for Average Joe. And you know what? I'm actually pretty OK with that, the open world Rift content is one of the aspects I quite enjoy about the game (even if I find Hunt Rifts to be painfully boring when done for any stretch of time), and it's one of the games strong points.
AoC has had only one expansion but they have put out some "adventure" packs (very much like the upcoming swtor "expansion"). Lotro has done fairly well with releasing content, well that depends on who you talk to I guess, but from the outside looking in, they seem to be doing well. Going F2P is not a death notice to an mmo, just have to be smart about doing it.