my point comes from what have said Yoshida about bring new jobs in the game, what about the fact that they must bring something new to the game and the party.
sam as tank is too close of war and drk for be really bring something news. the only difference will be mainly the gimmicks.... no new mechanic.

where dark knight and war differer is in the use of the ressource, one is mostly throught tp the other is more mana.
samurai is not a caster, meaning most of him technic will be tp focus, one more time close of what we have already. your point are simply ignoring this... you think:" we need more tank and i want samurai as tank" ignoring the fact that samurai is redundant with war and drk.

if they want to bring another tank, they need to create a new mechanic and something different, not that close of what we have already. what will be the samurai niche?
more a damage dealer tank, more a resilient tank, more a magical tank... no as a samurai he will really on counter, what is quite random, without forget the classe already present are doing it too, they have counter skill. but they are too limited for be really good as mechanic.

they will have more opportunity to create something news with caster tank or even a pet tank, than a samurai tank.

you absolutly want a samurai tank, because you love samurai and playing tank periode, not because it's needed or will bring anything news to the game. Samurai as tank will bring nothing new to the tank role. plus it will not help the tank population to increase, if people don't want to play tank even if they love the class, they will not play tank.

My point is from what we have already as tank jobs.... Samurai is too close of warrior and dark knight for be a good choice. it will be a weak choice and will not help the game to become better.

ps: i do have the three tank maxed, and did play them quite a lot, however i fail to see how add samurai will help the tank role... bring something news is needed.
about casting spell as a tank, i must recall to a lot of you that tank role are the one that must move only when is absolutly needed, it's one of the less moving role. meaning it have all the freedom to cast spell.