This show does not make much sense, really.
Firstly, how can you have a skill and not know its effects? Even if it's a passive skill, but is activated under unique conditions, if you encounter it multiple times - you will know. If not you - your party members, because they would probably notice. And the premise of the show is that they did notice the skill's effects. But somehow they noticed effect on the tank, not on them.
Secondly, even if effect would still be unknown because "reasons": his skill protecting the shields of other party members does not make sense. Not in a way, that there would not be such a skill: paladins in FFXIV have "Cover" that redirect damage from target to paladin (or at least they used to have it). But the tank was losing extra points when being targeted by single-target attacks, so why would that "protect" his party members' shields?
Thirdly, why is there even a limit of 6 people in the party? This is clearly not a game, where party limits are enforced due to technical and/or content reasons. What could be a logical explanation for this here? Besides, even if there was a reason, it was clear that only that "hero" was willing to replace the tank, so why every one else did not leave, if they did not share his opinion? But even with assumption of his "high rank", it would make much more sense to try to understand what has changed (because skill effects were clearly new), rather than just say "you are bad tank".
