I've created Guardian for this first BWE and quickly came to limits with the play style I prefer:
Being melee, whether with Mace, Sword or Greatword offered some nice skills, but once you had a few more opponents, things start to get laggy (it is a beta, and will probably get better) and distractingly flashy (we have already talked about particle effects). Quickly I started to use "wild button smashing" as I could not react to foes by observing what they did.
Now the question for people having more experience with the Guardian:
Can you make a good and useful Guardian by keeping to ranged weapons, like the staff or Scepter + Off-Hand-Weapons? Do you need to be able to swap in a melee weapon to not lose aspects of the class?