Over and over, the Outer Senshi prove they will do whatever it takes to accomplish their mission. But they fail, over and over, sometimes in spectacularly stupid ways. They are willing to let people die in order to get the Talismans...which it turns out that they ALREADY HAD. We'll leave aside the question of why Setsuna DIDN'T tell them when she must have known. However, the person who keeps this from turning into a complete disaster is... Usagi. The person they most tried to keep away from the Cathedral. The person whose transformation brooch they stole. A person who has every reason to dislike or hate them, but she risks her life, without her powers, to try to save theirs. Through her power, the Talismans are saved and the Grail is found.
But do they learn ANYTHING from this? Nope. They're back to treating the Inners as little hopeless kids in no time at all. They blunder their way through the rest of S, often doing nothing whatsover except lurk and look cool. Of course, this is partly the story editor's fault as well as theirs...Still, they set out on their own to defeat the forces of evil, rather than trying to oh, say...cooperate with other people with the same goal? The result? They get their ass kicked. In the end, it's Sailor Moon who helps Hotaru to overcome Mistress 9 and Sailor Moon who stops the rampaging Sailor Saturn AND Master Pharoah 90. And she does it all without ever once having to cross the moral line, without having to do the sort of thing that Haruka and Michiru congratulate themselves on their willingness to do for the greater good.
It happens again in Stars. Haruka and Michiru spend episode after episode totally distrusting the Starlights and wrecking any hope of real cooperation with them. As a result, the final battle with Galaxia turns into a complete disaster. Not that a coordinated effort would have had much more hope, but it would at least have been a moral victory, instead of a shambles. Instead, first the Outers fail to cooperate with the Senshi, then they try to trick Galaxia by 'selling out'. Their real goal is to get the special bracelets so they can blast her. Unfortunately...Galaxia isn't dumb enough to give anyone something they can turn against her. Pluto and Saturn fall to the 'traitor' Uranus and Neptune, then Galaxia kicks Uranus and Neptune's ass when they try to turn the bracelets on her. Again, their willingness to cross the line results only in failure.