Yes and no. I'm a DK in 346 blues. This is what I do when tanking 85 heroics atm:
Dead Mines: No CC needed, though it can help with pirates on the boat.
Shadowfang Keep: No CC. Trash doesn't hit hard to for it to be needed on a well geared tank.
Grim Batol: For first half of the instance were trash groups are at 30-50%, I generally don't do any cc since we're aoeing the groups down. A banish or mind control can still be extremely nice though. For the second half of the instance, CC is very nice to have.
Halls of Origination: Trash is trivial, no CC is needed.
Lost City: Trash is trivial, no CC is needed.
Vortex Pinnacle: Here you really do want some CC, because some of the trash is nasty. Doing the elemental packs up to first boss without any kind of cc for elementals is not fun, nor the last humanoid packs before last boss.
Blackrock Caverns: Whatever, kinda. If I have good cc in the group, I might use it, but it's far from needed.
Stonecore: Without CC you're in for a rough time.
Throne of the Tides: Like Stonecore. Doable without CC, but very rough.
So, that leaves us with: 4 heroics where CC only slows you down, 2 where it doesn't really matter much either way, and 3 heroics were you absolutely want CC unless you're prepared to wipe here and there.
This is assuming you have a skilled and decently geared tank. If you're doing randoms and run into a bad tank, any CC is most likely gonna help the group out a lot.
For OP: I imagine 30 sec CD on DnD is very annoying on live if you have dps aoeing from the start, like they've been doing for the last 2 years. For cataclysm though, 19/20 times your DnD CD will be up for every new trash pack. At least until your group outgears the instance by several tiers, pulling 20k+, then it's gonna be a problem again.