Warrior is awesome, but there's too many of us right now. It's hard to find parties. Bard, scout, mage, and psi will not have this problem.
Regarding psi, you do have some spells with zero to low cast time, but using this kind of build in group PvE situation is sub par and gimping yourself. Main problems with psi is that the go-to group PvE (when you have someone else taking hits) and solo farming builds are drastically different, keep in mind re-spec cost is horrendously high.
Also you are going to have mana problems and will burn mana potions like crazy with the solo build (even with Superficial Trance and 2-h weapon).
Psi's damage is balanced around keeping a 20% damage debuff - Mental Link/Will Suppression on the target and has a lot of very troublesome and clunky mechanics - stacking buffs and debuffs.
To be honest, I would not advise you playing this class, with the removal of Conviction and the whole new Willpower system it's just a very watered-down and gimped version of the Mage.