I've never tried this instance without a tank type.

I found close to 60th, this required a lot of fire resistance gear.
With the gear, it was fairly easy with either pally aura or shaman totem.
Without the gear, it was not doable.

Towards 70th, I didn't need any form of resist gear to run this with ease.
Was farming the rings with armor and resilience on my feral druid solo.
That was before boxing.

Heroics required the resist gear again, but with a half decent group.
And a few piece of resist gear, this was a pretty easy fight.

So common theme here..
Resist gear is huge for this, if you're doing it at an appropriate level.

If you can get barely in range of the dragon.
And nuke him in the air, without aggroing the guards.
That would make it a lot easier too.
The rider is no big deal.
It's the fire that sucks.