The expanded classes are gimmicks. The Ninja class makes a better AoE caster than a pre-trans Wizard but consumes items to cast (that you have to go all the way to Amatsu to get). They can't wear any of the good mage gear like Orleans or Survivor's sets, so things like Phen clips are a must. Their best weapon is the Bazerald which only gives a pitiful +10% MATK (but +5 INT) and is an MVP drop. Compare this to the Arc Wand which is NPCable and gives +3 INT and 15% MATK. While damage isn't as important for an AoE caster in group play, it doesn't help win you any popularity points being outdamaged by Wizards in NPC gear.
Post trans though High Wizzie/Sniper make better mob controllers than a Ninja ever will thanks to the extra trans stat points. Ninja also gets a very poor INT job bonus (+5) vs the High Wizard's jaw dropping +17 at 70. Ninjas have a relatively poor SP pool to begin with, whereas HWizzies get 2 free SP regen levels for essentially free. Sniper gets the excellent Sharp Shooting skill which can essentially become any element thanks to arrows, sucks to be you if you're a Ninja fighting undead or frost resistant enemies. Watery Evasion can take the place of Quagmire and serves dual purpose to give HWizzies water to cast Water Ball which is kinda neat, although Quagmire is better as it drops AGI/DEX in half compared to only -8 AGI drop. Scholars can do that too with Deluge though while boosting the Water Ball attack power at the same time (and not cripple the HWizzie that has to venture into the water with half movement speed).
Only thing Ninja brings to the table is survivability with Cicada Skin Shed and Flip Tatami, which 1) isn't needed in group play and 2) is easily bypassed with trans skills like Acid Demo and High Speed Cart Ram.
I rolled one as an alt simply because Ninjas are still my favorite magic-based class (second being battle sages). They play much differently than a straight up Wizard thanks to CSS, and they get better wind elemental spells than Wizards get.
