the trouble with samurai as tank, and it was pointed countless time but ignored by some, is... it will be:
- a two hand sword class (like the dark knight)
- based on parry (like dark knight and warrior)
- mostly physical damage (like paladin and warrior)
- wearing heavy armor (like every tank)

the point is the samurai as tank is only a skin.... we already have a jobs with 2 hand sword as tank... and one based on parry. what the point to add one more jobs like this? i see more a magic melee tank that will bring novelty and new gameplay to the tank, more than samurai that some want simply because.... they want samurai as tank.

as tank it will bring nothing new to the jobs. when a tank based on a caster can be quite interesting and have a few way to be added. because dark knight is not really a caster tank, is more a bad hybrid with more a melee with a few ability draining him mp... don't make it a caster tank.

and just a particularity into the combo system is not enough for justify to add samurai as tank.