Every possible role and niche is filled already by what we have. Right now a new class won't really offer anything new to combat.
Personally I wish for more weapons and skills for each class.
We need multiple options with current weapons, for example:
Sword Main-hand mesmer-
Skill 1 - choose ability 1/2/3
Skill 2 - choose ability 1/2/3
Just to spice it up a little bit, instead of the same 4 abilities other than autos.
We need more variety in builds.