Nothing is being removed from Raid Finder. In fact, the rewards Ghostcrawler mentioned in his tweets
are something brand new that haven’t previously been available in any raid content.
We want there to be some incentives to “make the jump” from Raid Finder into something more organized. However, we’d like to do that in a way that doesn’t take anything away from Raid Finder. So instead of removing set bonuses, trinkets, legendary progress, or anything else along those lines, we decided to come up with something new.
Just to be totally clear: Raid Finder in Patch 5.4 will be itemized with all the same sorts of stuff you’ve come to expect over the last couple of tiers. There will, however, be a brand spanking new type of reward that is only available to players who choose to step up into Flex, Normal, or Heroic raiding. Hope that clears the air a bit! :)