When I started playing WoW in classic, bears were really a bleak copy of protection warriors. Fast forward to Cataclysm. How do they feel today?
Identical abilitiesThe first comparison isn't even fair. Growl and Taunt are the identically same abilities, but they're also identical to Hand of Reckoning and Dark Command.
Moving on, Demoralizing Roar and Demoralizing Shout are identical. So are Challenging Roar and Challenging Shout. Interestingly enough, druids can glyph their version for 30 sec less cooldown, but I haven't been able to find a similar glyph for warriors. However, they pick up a talent (Drums of War) which reduces the rage cost of both shouts to 0 rage. Most handy.
Maul and Heroic Strike are basically the same. However, glyphed Maul will hit an additional target (albeit for 50%), which is starting to remind very much of Cleave. Then again, glyphed Cleave hits two additional target.
Similar abilitiesSurvival Instincts reduces damage by 60%, while Shield Wall reduces damage by 40%... however the latter can be glyphed to reduce damage by 60% as well, increasing its cooldown. However, with the talent Shield Mastery, the cooldown, even glyphed, drops below that of Survival Instincts.
Bash and Concussive Blow are pretty similar. The main difference is that Concussive Shot has a shorter cooldown and deals damage as well. Still, pretty similar.
Skull bash and Shield Bash are also similar, though Shield Bash has two seconds longer cooldown (provided the bear picks up Brutal Impact, which every bear with a bit of self-respect should). Shield Bash is affected by a lot of talents, though, among others reducing the rage cost to 0 and granting it a 100% chance to silence and daze the target.
Frenzied Regeneration now increases health by 30%, just like Last Stand. It also converts rage to health, similar to Enraged Regenration. The glyphed version increases healing taken instead.
Abilities which have the same purposeNow we're arrived at abilities which aren't necessarily very similar, but works for the same purpose.
First, the primary skill for each spec. Mangle and Shield Slam both share a 6 second cooldown and are high-threat single-target moves. Mangle also applies a bleed debuff, while Shield Slam removes a magic buff. Both abilities have talents which gives a proc that reset their cooldown and cause them to cost no rage. For druids, it procs of Lacerate ticks, while warriors proc them off Devestate and Revenge.
Thunder Clap and Swipe are both AoE-threat abilities which share a 6 sec cooldown. In addition, Thunder Clap reduces attack speed of the opponents. Druids have this ability attached to Mangle and Maul with the talent Infected Wounds. In addition, Infected Wounds slow the target.
Druids also get a second AoE-threat ability on a 6 sec cooldown at level 81, Thrash, which applies a bleed effect to all targets. Warriors can talent Thunder Clap to spread the bleed from a Rend to all targets.
Then there's gap closers. Feral Charge and Charge both share a 15 sec cooldown unglyphed, 14 sec glyphed. The druid version immobilizes the opponent, the warrior version stuns. However, protection warriors also have Intercept and soon Heroic Leap.
Druids get Omen of Clarity for free, allowing a rage free ability now and then. Warriors can spec into Battle Trance, which does pretty much the same, but has a higher proc chance from a smaller selection of abilities... namely Shield Slam only.
Stuff which are not so similarFaerie Fire and Devastate (or Sunder Armor for low-level warriors) both reduce armor by 4% and stack up to 3. However, they are not very identical in the way they are handled in the rotation. Faerie Fire has a long reach, a 6 sec cooldown, and with an almost mandatory bear talent (Feral Aggression) applies 3 stacks each cast. Thus, a druid doesn't spend time stacking up FF.
However, druids stack Lacerate 3 times. They throw down Pulverize to consume the stack and get a self-buff, unlike warriors who just keep Sunder Armor up throughout the battle.
Warriors do have a bleed, Rend, but it isn't vitally important the way Lacerate is.
Barkskin and Shield Block have some resemblance in usage as both reduce incoming damage slightly on a fairly short cooldown. Talented, Shield Block only has 30 sec CD, while Barkskin remains at 1 min. In addition, with Heavy Repercussions Shield Block becomes an offensive utility as well, doubling the damage of Shield Slam while it is up.
The passive mechanic to block incoming attacks for a warrior has somewhat the same purpose as Savage Defense, namely reduce incoming damage somewhat. Both are also focus of the mastery for each class.
Unique abilities to each classEnrage was originally a copy of the warrior ability Bloodrage. However, it is now gone, leaving druids with an original ability.
In addition to some abilities mentioned above, druids also get Berserk, Stampeding Roar and Omen of Clarity. It might be mentioned that druids also get Rebirth, one of the very few ways to bring someone back to life mid-combat. Useful also for a tank, in a fight with phases where they can shift out between the different phases without risking to get squashed.
Warriors get a heapload of original stuff they can use while tanking. Which isn't too strange, since they can't shift out of their rage-form, like druids can. Listing them quickly: Intervene, Slam (not sure this is of any use while tanking), Vigilance, Shockwave, Disarm, Revenge, Spell Reflection, Heroic Throw, Victory Rush, Inner Rage, Berserker Rage and Intimidating Shout.
The two classes also bring different buffs and debuffs which benefit their party/raid. Well, almost. Both bring the armor reduction debuff. In addition, druids bring Leader of the Pack, the Mangle bleed increase and Mark of the Wild. Warriors bring Battle Shout, Commanding Shout and Vigilance. It feels like I've forgotten something here.