Which class is more needed?
Both are needed, most 8-man raids will prefer to use both for the debuffs and to build the limit break break.

Which class is preferable?
This wont be reliable as I can only say for the server I'm in but it would seem that the paladin is the more popular choice for other people but that really depends on who you run with, how they heal, do you know what you are doing etc.

Which class is least played?
Warrior is the least played out of the two but when the buffed them more people started to see it as a viable option

Warrior or Paladin?
I have a bias towards paladin as its my main, I enjoy the security of the paladin with its cooldowns and hallowed ground has to be one of, if not the most useful cooldown in the game. That being said I enjoy warrior because its fun to play and dps can help in some situations.


Any tank worth their salt should have both at 50 to see what they enjoy but also to roll as to benefit the team.