Kiting as a druid tank is trivial, just shift to cat form and run pretty much anywhere you want. You can actually build enough distance to stop and Rebirth someone if they're in your kite path.

Every tank has an escape method to gain ground while kiting. Intervene (or intercept a vapor), Unholy Presence, kitty sprint, and Pursuit of Justice. Body and Soul is there for the moments something goes wrong, or you can have a hunter Pack you out during cast time. It's a non-issue for good tanks.

A DK tank gives you the option of using Icebound Fortitude on every surge instead kiting the boss. This tremendously simplifies the fight -- we one-shot him the very first time we tried it.

It doesn't take very many cooldowns on any tank to survive. DK tanks obviously can do it themselves.

We used a warrior tank and with his enrage timer at 10 minutes, you've only got to survive 9 of those buffs(if the fight goes that long) 5 of them (#1, #3, #5, #7, and #9) can be dealt with by Shield Wall.
The other 4, the warrior pops his other cooldowns and either Pain Suppression, Guardian Spirit, or the pally buff (I'm sorry, I forget the name) covers it. It's obviously more complicated than a DK, but you've got 2 minutes in between ones healers need to help on, and we just call out in advance which healer is going to be responsible this time (or whether the tank is going to just shield wall it)

Edit:
Once we did that Searing Flames was the only issue. Kiting him just makes that harder. We also ended up asking our Enh. Shaman to stop using Earth Shock in his rotation. It hurt his DPS but he'd screw up the kick timing of the rogues since he'd lock-out only for 2 seconds. The rogue kicking seemed to get much better after that.

Why would you not kite the boss, except maybe for the 1st surge when the tank is trying to get a good hold on aggro? Kiting reduces immensely the damage you take since every minute you can spend 15s not getting hit at all. Kiting surges offers 25% less damage taken when compared to a strategy that uses a DK tanking with IBF all the fight. Healer positioning is not an issue because you can safely kite between two predefined positions, with healers standing in the middle.

Having only done this with a fixed-position tank, the answer I'd say is that healing is very light anyway, especially if your ranged is avoiding the shadow crashes and you are interrupting the flames. So this just lets everyone more or less get into position and stay in position.

Basically it's the same with Emalon. You just heal your tank through the nova instead of letting him run out and in again (at least on our server).
Of course you're right that kiting should reduce damage taken. But your tank, your healers or your interrupts could mess the kiting phase up ending probably in a wipe.
In my opinion a static fight is always easier and hey, cooldowns are there to be used.

It is not absolutely necessary when it has been beaten on hard mode without the use of kiting. Both methods are viable for both modes of the fight.

The tradeoff is that by keeping the boss still you increase DPS, which makes the fight shorter. It's a valid discussion.

Furthermore, I'm a little curious what else about the fight is worth discussing. Strategically, you want your ranged dps to be spread out some distance from the boss so that no one gets hit by shadow crash and yet people can quickly get to the residue to dps from it. That much seems obvious.

I suppose one can argue about where to put the healers, altho it seems fairly obvious that melee range is safer with no discernable downside other than a guarantee they have to move in order to pick up the cloud residues.

This fight reminds me a lot of Void Reaver, of all things: There is a core mechanic that has a lot of people running around, but the fewer people you can get by with running around, the better off you are.

Has anyone tried the [Darkmoon Card: Illusion] on Vezax? Would be nice to know if the triggered mana effect works on this fight.