Ranger Difficulty: very easy

Hunter Difficulty: medium

Short to medium ranged moderate sustained damage dealer. Reduced damage in close range.

Warrior Difficulty: easy

Short ranged high sustained damage dealer.

Rogue Difficulty: medium

Quick, fragile, high burst damage. Primarily melee with strong close-quarter attacks with a few gap closer skills and short duration stealth. (Guild Wars 2 style thief)

Elementalist Difficulty: hard

Short to medium ranged enchantment-based attacks dealing moderate damage. (Think Legend of Korra)