I've been getting a lot of email, and pings on twitter, about finishing out tier 14 raiding. While patch 5.2 is coming and the new tier with it, a lot of folks are still working on finishing out tier 14, be it normal or heroic. It's a fair point, the patch is still at least a few weeks away, so focus on the current one while it is still relevant. That doesn't mean though that you can't prepare a little bit for the future while handling the here and now.
Getting through the content that is current will net you decent gear and experience that will be valuable going into the next tier of content, especially if you are getting some time in on heroic bosses of tier 14.