Skill levelling got again quite important with subclassing. If you pick up a skill tree that you have not mastered you have to level it up again to unlock skills, morphs and passives.
This is really easy for a dd: Consume a learning scroll go to a place with a lot of low level npc (like that spot in carglorn, there are other places as well) where you collect a mob and then slay it down with added skills from the new tree. The more npc you kill the more exp you get and this is multiplied by the scroll learning factor.
If possible unlock and slot the green cp tree perk for additional 3% per stage exp gain.
In no time the skill tree is at level 50.
Now as a tank (or a heal) you don't have a lot of damage.
Consequence is: you cannot take as much mobs as a dd can. In addition you don't do much damage. So the exp grind this way is really really slow!
Now in general if I build a tank with subclassing I try to combine three trees that are good for tanking and ... not good for damage.
So all class skills available don't do much damage.
Of course I could put some skills from the weapon trees. But still I won't to as much damage as a pure dd could and hence level my skills slower.
Of course I could as well build a dd with 2 damage skill lines and one tank skill line that I want to level and do that. Then I swap the new skill tree with another skill tree for my tank and level this. Again this takes more time and costs at least 4500g (2x1500 and another 1500 to finish my tank build again after levelling is finished).
Another way is making quests, play dailies. It however takes quite some time.
Usually with a dd I would have finished my leveling in one evening. At the moment I am about level 30 for the skills for my tank after the same time spent.
Please offer some tank perks that allow leveling faster for tank (heal) skill lines. Taunting should give a small amount of exp. Taking damage without dying should give exp, maybe proportional to the damage taken without dying.