Basically, what this will do is allow people who don't like to raid (or don't have the time to or feel they will be a liability) to continue on with the story, the characters will act like the raid was completed, though you won't get any rewards. If you want any of the rewards for the raid, even the LFR version, you will have to actually do the raid. I know, might be some people who say "if you can't beat the raid, you should't be able to progress in the story" or something like that.