To play mesmer you have to be fast and reposition all the time. I usually play staff and blink with staff 2, I also take blink ult and blink stun break. When my blinks are in cd I use my axe 3 and dodge. Mesmer is all about not to be caught.
I've played all classes with mostly all meta builds. Compared to ele, guardian, necro, deadeye, revnant mesmer is very far from been op.
And yes in raids mesmer is op atm, but I really don't wanna get nerfed in pvp cuz of pve content lol. In pvp mesmer is a kitten compared to necro and needs a huge buff to become somehow equal.