Lurker was not a kraken model.

It does have a Kraken model. Just google it and you'll see.

The Lurker Below does not look like a traditional Kraken, but the model name has "kraken" in it. It's also the same exact model as the Kraken the author wants to see as a boss, so I dunno what's up with that, as the Lurker Below was a raid boss before these single-player quests.

i love the kraken idea! couldn't they make a kraken on a huge travelling pattern with a super-low spawn time, like the time-lost proto drake? that would eliminate a lot of the problems that existed with world bosses in the past.

Actually, Frank, that's exactly the problem there already was with world bosses.

Long spawn times reward those who track them religiously. What used to happen was you'd have world bosses (such as the dragons) on set spawn timers of, say, 96 hours from when the boss last died. So whoever last killed it would typically be standing right there waiting 4 days later when the boss respawned, and the end result was that 95% of the raiding guilds never saw the boss because the same single guild would kill it every respawn cycle.

What could be interesting is to exploit phasing with the world bosses. For example, set it up so that when you kill one, you can't see it again for a week, while the actual respawn time sits closer to a few hours.

My major concern, though, is that world bosses almost have to be balanced around a 40-man raid by default. Unless you implement some clunky mechanic to limit raid size (like giving the boss an ability that kills anyone who has engaged it in combat above/beyond 25 people?) balancing for anything less than 40 trivializes the encounter, because you'll always have people bringing 40 men to kill it, instead of developing the skill necessary to down it with 25.

Lastly, world bosses tend to allow for graveyard zerg strategies, and I really don't want to see those come back.

I didn't play in Vanilla, so I can't say if it was before TLB or not, but there is a quest in Dustwallow Marsh for alliance where you kill a beast with that model by the use of cannons. Tethyr is his name.

There are no mentionings of him being added in a later patch on wowwiki, so I guess this is the first implementation of the Kraken model.

Tethyr and the associated quests were added during the revamp of dustwallow in BC.