Oh the possibilities...
So I haven't seen the new codex, seeing as how I'm poor. But boy howdy... I've been reading back through the 6th ed. 40k rules and things are going to get interesting. Stop, for a moment, if you will, and consider the Crisis Suit.
In 5th ed., you could move 6" in movement, then shoot in the shooty phase, then move 6" back into cover (or wherever else you wanted) during the assault phase because you're a Jet Pack model. Pretty nifty all by itself. But 6th ed. changed that just a scootch. For the better, in my opinion.
You can now move 2D6 in the assault phase. Now, 2D6 averages out to a roll of 7, so on average, you'll be rolling with more movement than before already. BUT... on a good day, you'll have 12" of movement. Can you imagine the insane movement possible with a secondary move like that? Talk about the potential to dominate the enemy! Now, conversely, on a bad day, you'll only have 2" to move. On those days, it's a good thing your Crisis suits can take a beating :D
I've been holding off on really delving into the new rules until I can get the new Codex in hand, since I don't know what else GW will have meddled with, but I can tell you this: There will be LOTS of tactics posts up here one I get the Codex :D
Stay tuned, followers of the greater good! There's plenty more where that came from!