For me, I do the last phases as follows. Starting from the return of Nael.

fast blade
savage blade
tempered will
rage of halone
fast blade
savage blade
rage of halone
fight or flight
fast blade
convalescence
savage blade
foresight
rage of halone
shield lob add
(if distant location: shield lob add again)
spirits within
circle of scorn
combo repeat till fire aoe skill
By this time the dragon is as good as dead for us and Nael is already close to P4.

Move, follow the regular tactics and do your usual tanking. As for my cooldown rotation on the following claws:

Claw 1: Rampart
Claw 2: Sentinel
Claw 3: Rampart
Claw 4: Hallowed Ground
Claw 5: Rampart
Claw 6: Sentinel
Boss dead.

Claw 1, 3 and 5 don't really hurt that much. So you might even let those CD's go there. Outside of those moments, incoming damage is low. There's little need for CD's. As there's no cleaving, there's no need to turn the boss away from group mates. Better yet, for the fire in you're going to want to have them stacked on you. Only exception is after the 2nd divebomb 1 and 2nd divebomb 3. Then you want to be standing center by yourself till Nael crashed down on you.