This is something I think takes a little transition as well. Most good tanks are used to the rhythm of marking, being methodical, and repeating the process from group to group for a smooth transition. However, the game has changed slightly, so feel free to change your tactics. As Dreador mentioned, sometimes the best way to go through an instance if you feel that your healer isn't stressed out is to just jump in and use our wonderful new AOE skills. As long as your healer isn't freaking out in trying to keep you alive, don't give the chance for your DPSers to pull. Rush in and do your thing. If you feel that the healer can't keep up, or if you find that it's getting a bit rocky, then fall back to a more conservative stance. (Mark, etc.)
Honestly, it's a lot of fun to rip things up if we're able to! Save the conservative planning for the places that really need it. Chances are, you'll have plenty of that to go around in the future. Live it up as a wrecking ball while you still can.
Stay strong. Stay smart. All heart.