[Jay]

Attacker: http://i.imgur.com/SAi0JNl.png
--> Their stats aren't at all above average. This strength is easily achieved unintentionally.
--> Essentially casting a 10 FP crit-able spell that scales on the melee stat (STR).
--> Just as much (if not too much) elemental diversity like an evoker. (see: elemental sword weapons)

Defender 1: Average defense and average res -- DEF Black Knight
--> HP: http://i.imgur.com/9kvZMqa.png
--> DEF/RES: http://i.imgur.com/EVC4kvt.png

Attacker attacks Defender 1 with Malakh and hits them!Defender 1 takes 36 Slash damage.
Basic Attack
Attacker attacks Defender 1 with Malakh and hits them!Defender 1 takes 54 Slash damage.
Basic Attack + Absolute Death

Attacker attacks Defender 1 with Malakh and hits them!Defender 1 takes 100 Slash damage.
Power Gradation
Attacker attacks Defender 1 with Malakh and hits them!Defender 1 takes 150 Slash damage.
Power Gradation + Absolute Death

Defender 2: Slightly above Average defense and slightly above average res -- DEF Black Knight.
--> HP: http://i.imgur.com/vH965B8.png
--> DEF/RES: http://i.imgur.com/TPhhyWn.png

Attacker attacks Defender 2 with Malakh and hits them!Defender 2 takes 30 Slash damage.
Basic Attack
Attacker attacks Defender 2 with Malakh and hits them!Defender 2 takes 45 Slash damage.
Basic Attack + Absolute Death

Attacker attacks Defender 2 with Malakh and hits them!Defender 2 takes 91 Slash damage.
Power Gradation
Attacker attacks Defender 2 with Malakh and hits them!Defender 2 takes 136 Slash damage.
Power Gradation + Absolute Death

Note: Tanks cannot avoid this attack. So inaccuracy is irrelevant.
Note: The average tank with decent DEF only has about 15 or less RES.
Note: Non-criticals against Black Knights.

Proposals
--> Adjusting the FP cost. Starting from 30-35 FP at rank 1 to 20-25 FP at max rank.
--> Negating criticals with the skill. It already receives boosts from skills such as AD.
--> Keeping the damage type slash regardless of weapon choice OR give it an element that cannot be changed.

I do not want to ramble too much, because it's an issue relative to everyone. It doesn't seem right that a melee class can nuke tanks like an evoker. If you have different proposals or feel the need to rebuttal (with some value), please do.