@Greg reece

Blizzard never said that they don't want tanks handling interrupts. and Paladins are the only tank without one at the moment. Druids have skull bash on a 10 second Cooldown, DKs have Mind Freeze on a 10 second CD, Warriors have Shield Bash on a 12 second CD, and Pummel on a ten second CD. All off the GCD. Paladins have Hammer of Justice on a 60 second CD, on the GCD. That's a noticable disadvantage.

As for not tanking multiple mobs. I've tanked multiple bosses on every council fight released. I tanked two members of the Iron Council, two members of the Blood Prince council, two members of the Wizard of Oz in Kara. I've tanked multiple adds on practically every fight that has them. Lady Deathwhisper, Gunship, Valithria, and the Lich King, in ICC alone. These style of encounters will continue in Cataclysm, as the Twilight Council and the Conclave of the Wind show 2 council fights in the first tier alone.

You're confusing the bosses with absurd melee damage, like Ignis and XT, with the bosses that had reliable burst abilities that require CDs, like Sarth, Steelbreaker, Hodir, Mimiron, Vezax, and Algalon. The absurd melee damage has been toned down since Ulduar, however, fights like Gormak, Anubarak, Festergut, Sindragosa, and the Lich King show that the cooldown rotation model of boss damage is alive and well. Those are the fights where multiple cooldowns shine, and those, aside from Gormak, were all fights that DKs excelled at.

The change to incoming damage has been harkened as a return to BC style encounters. Where... tanks stacked stam, were integral parts of interrupt rotations, and lived and died by CD rotations on encounters like Illidan and Felmyst. In the ICC raiding environment, there isn't a single boss that can two shot a decently geared tank with a non timed attack. Festergut's inhales are on a timer, as is Sindragosa's blistering cold, the shambling Horror's enrage, and the Lich King's Soul reaper. survival CDs are no longer the provebial "Oh Shit button", they are to be saved for a specific point in an encounter, and if you slip up, and miss the CD, or pop it early, the raid will wipe. It's not designed to challenge healers, because if the CD is there, the damage is nothing special, it's designed to challenge raid coordination. If your tank can handle them all, by himself, you stand a much better chance of success than if you had to rely on two or three other players to handle that on top of their normal duties.