Love the Stone Crusher Carnifex model. Don't think footslogging works at all as you can't take as a pack of 3 annoyingly. Think they're amazing with the claws at Anti-Tank (5dmg rerolling 1's hitting on 3' str 14) + Mortal wounds on the charge.
Just thinking if I had at least 1 in a Tyrannocyte deep striking, would it make it viable? That's 200pts for a heat sinking missile. But at least once he's dead you've got the Tyrannocyte hanging around being a nuisance?
I'll be running Behemoth also (painting up an old school 3rd edition scheme) and think rerolling out of deepstrike is probably the best hive fleet (I'm running alot of big monsters in my list like the Dima + Swarmlord).
Or just spend a few more points for a Scythed Hierodule....