This is a somewhat spoilery post if you haven't yet completed the campaign, you have been warned!
The way that the Elder Dragons were sold to us pre-release suggested that they were not typical "scaly-fire-breathy-big-toothy" dragons, but more embodiments of extreme hate, hunger, lust and greed. Whirling tumults of death and destruction whose very presence can send people mad, corrupt the souls of lesser beings and burn a river of pain onto the landscape.
These are the beings which roamed Tyria before even the human gods, before any of the current surface dwellers were even scratching glyphs into cave walls, even before Trahearne was hatching his scheme to recruit a young player to come and save the world so he can take credit. The Elder Dragons are primeval in the truest sense.
Similarly, anyone who has fought one of the Elder Dragons champions would surely attest to their power. The Claw of Jormag summons great waves of ice and pain, and springs shards out of the ground which impale unsuspecting players. It takes 40+ players and half of the pact army just to bring him to the ground. Have you seen the size of the laser we have to use to take down Tequila Sunri... I mean Tequatl the Sunless? The Shatterer - well, the less said about the Shatterer the better really (can we ramp up his difficulty plox ANet? Kay. Thanks).
Anyway, my point is that once you've fought your way through these dragon peons you'd be forgiven for quaking in your boots at the prospect of having to fight the big cheese! The big-cheese turns out to be more of a Baby-Bel. Less of a "whirling tumult of death and destruction" and more of a "spinning top of farts and disappointment".
The encounter with Zaitan is 15mins of work at best, most of it spent sitting on a mounted cannon and hitting 1 - hoping that you're actually doing some damage (this isn't really that clear). Zaitan clings to a mountainside and just takes it, like an abused triceratops plushie tied to the front of an articulated lorry. "Stop iiiitt, owweee, Stoooop iiit - guys!".
It just wasn't as epic as I thought it was going to be. He's an Elder Dragon for crying out loud - if it takes a whole army of us to take down one of his minions, we shouldn't be able to take him out with a flying boat and rag-tag group of adventurers (particularly if said adventurers keep throwing themselves off the flying boat just to see what happens - "weeeeeeeeeeeeeeeeeeeeeeee splat").
I think ANet should have taken a leaf out of Squeenix's book in an attempt to make the battle more epic. The way they framed the antagonist "Sin" in Final Fantasy X was fantastic, you felt genuine dread thinking that you would soon be facing an enemy of such an epic scale, and that is because they approached the battle with delicacy. The stories are relatively similar - gigantic embodiment of evil emerges from the ether, begins destroying world, spawns "Sinspawn" minions, group of adventurers take to the skies to take him down (obviously FFX has extra layers: the origin of sin, the history etc - brilliant game, btw).
Sin is so fantastically epic that the players cannot face him head on, they would simply be annihilated - so you have to whittle him down - facing his eye, his fin, his arsehole etc. Before finally travelling inside Sin himself to destroy the essence inside. Now - I'm not saying that ANet should have followed this process exactly but they could certainly have learnt some lessons:
1) You cannot just plop the big-bad on a shelf and allow us to take pot-shots at him. This just cannot happen, this is the big-bad - he has to be so big and so bad that we cannot comprehend him. Yes, the twisting mass of snakes which Zaitan turned out to be was pretty cool, but he looked pretty small clinging to the mountainside like that. The cannons should have been Phase 1 of the battle - have us fire blindly into a cloud of dust which occasionally erupts with fire and lightning - with the odd snake's head or scaled tail whipping out to attack us. Tease us with the big reveal - don't just stick him out there for all to see.
2) He has to be a constant threat. Even in his weakened state, we should always feel like he might just be biding his time. I never once felt like he might win the battle. Give the poor guy some balls, for pities sake.
3) The killer always comes back for one last scare. Just when we think we've killed him, Zaitan should have leapt at the airship (possibly wrestling with the ship in a Gandalf vs Balrog style battle) and tore us to the ground. Then, emerging from the dust groggy and confused - he should have reared from the wreckage, weakened, but angrier than ever. This should have been the big reveal - rather than sticking him to a mountainside, have him rear up out of the ground and tower above us - forcing the player to crane their necks upwards to even get a look at his slavering muzzle.
4) If you're going to have us fight from an airship - at least keep the battle moving. We can both fly, there's lots of mountaintops to stop on - keep it active and interesting.
5) Finally, someone has to die. This is just a given. After the length of campaign which we endured, someone has to pop their clogs. That's how you scale the battle from 40+ people down to 5 and still maintain the epicness. As if you're saying this person made the "ultimate sacrifice" and that's why the battle was won. I think we all know who I mean here. Bloody leafy-freeloader.