(edited by Septic.3126)
What class should I choose?
Thieves are kings of mobility and burst; sounds like you’d enjoy playing one. In fact, they pretty much meet your specifications to a T.
Hmm, I’d advise Thief/Warrior/Mesmer if you are going for a mobile burst character. Thief might be currently the best package of mobility and burst of the three. You got a couple of builds but as long as you go shadow arts you can play like a leblanc or Zed like style. Warrior you can mix in massive teamfighting capabilities instead of just roaming if you want, I guess its more like your gragas but with more damage and being an unkillable tank. Mesmer feels kinda like thief just a bit weaker with a bit less mobility but can be fun if you prefer a caster play style. Also I’d imagine thiefs/warriors will be toned down slowly while memser will probably only rise from a buff/nerf standpoint so if you dont want to deal with nerfs to your main you could start here.